#help-27

1 messages · Page 380 of 1

misty crest
#

well yea? do you understand this

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if you understand this then it should be clear

hazy cypress
#

yes, but i don't get how it relates to my question. it seems like an unrelated fact

misty crest
#

it’s not at all unrelated

hazy cypress
#

i can understand that, i just don't understand how

misty crest
#

we first compute lim |a_{n + 1}/a_n| and after simplification we found that the limit equals
|x - 2|

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do you agree with this so far?

hazy cypress
#

yes

misty crest
#

ok and the ratio test tells us that if this limit is < 1 then the series for a_n converges

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since we are interested in where our series converge we should therefore set our limit < 1 to see what values of x make that inequality true

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doing so leads us to |x - 2| < 1

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we rewrite this as
-1 < x - 2 < 1 <—> 1 < x < 3

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so we know for sure that the series converges in this interval then we check the endpoints to see if it converges there as well

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you’re wondering why the radius is 1?

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the radius is the distance from the center

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the center here is 2

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|x - 2| < 1 means all points within a distance 1 from 2

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youll notice that for any power series we have some |x - c| term after our limit computation

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and the limit will always be of the form L * |x - c|

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we want this to be < 1 so we get
|x - c| < 1/L

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1/L would be our radius

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note that if L = 0 then
L * |x - c| < 1 always holds since 0 < 1 regardless of the value of x so our radius would be infinite in a sense

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and if L = inf then L * |x - c| < 1 would only hold if x = c

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every power series converges at its center (since we’re just summing zeros)

hazy cypress
#

sorry, gimme sec

#

got sidetracked

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i think i get it

misty crest
#

🔥

late void
#

she hugged me and I got tingles from it

misty crest
#

interesting

hazy cypress
#

.close

devout snowBOT
#
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hushed vault
#

How do I do number 5? I dunno what they mean by secant line 😭 😭

uncut crow
#

the line that goes through the 2 points

young spade
#

find a line of the form y = mx + b
that passes through the points (x1, f(x1)) and (x2,f(x2))

hushed vault
#

...how do i do that

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sorry

young spade
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In the previous problem you already solved what is the value of "m"

hushed vault
#

yeah for the slope

young spade
#

Now you only have to find what is b

#

For that you can solve a simple equation

hushed vault
#

do i have to do point slope form?

young spade
#

You can do that too, but its arguably easier to just find the value of b based on some of the two values of x1 or x2

#

$$f(x_1) = m x_1 + b$$
$$f(x_1) - m x_1 = b$$

woven radishBOT
young spade
#

And you already know what f(x1), m and x1 are.

#

you could do the same with x2, and prob you would be inclined to check with both just in case, both should give the same value for b.

hushed vault
#

that makes a lot more sense

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tysm

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i have another question aswell

young spade
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go ahead

hushed vault
#

in the picture i included it showed a table at the bottom, for number 9

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freak no

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sorry number 6

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the table is for problem no. 6

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and questions 8 and 9 are:

  1. Where is the rate of change constant?

  2. Write the equation that represents the average rate of change

young spade
#

To be really honest, youre probably a few classes away from knowing about derivatives and these problems are more suited for it. But we can do it with the avg change of rate too

hushed vault
#

ngl, this is my final review packet 😭

young spade
#

oh, lmao.

hushed vault
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yeah rip

young spade
#

Well, anyways, dont worry about it. We will work under the assumption that the avg rate of change is taken in ranges of length 1

hushed vault
#

mkay

young spade
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I hope you see that all ranges go from a to a+1

hushed vault
#

yeah

young spade
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Now, for 8, we would like a range that as a avg. rate of change of 0

hushed vault
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wait sorry, what does that mean

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im honestly so sorry, im kinda sick right now and all of this is a different language, i swear im smarter when unsick 😭

young spade
#

To be really honest, the question is a little ambiguous on words. I wont bore you on the why, but this function doesnt really have any place where the rate of change becomes actually constant.

hushed vault
#

for context, this is a first semester ap precalc packet if that helps?

young spade
#

But im mostly working in that they meant for a place in the function in where the avg rate of change is 0, aka, it says as is in the bounds of a range.

hushed vault
young spade
#

in another words, we would like the following:

#

remembering that all ranges go from a to a+1

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$\frac{f(a+1)-f(a)}{(a+1) - a} = 0$

woven radishBOT
young spade
#

I wrote it with parenthesis to make it obvious, but the denominator obviously simplifies to 1

#

And since the only way a fraction is = 0 is that the numerator is also = 0, then we can ignore the whole denominator part even if it wasnt 1.

hushed vault
#

okay, im gonna ask my teacher on monday just incase but i think you have it right so far

young spade
#

after simplification, we end up with

#

f(a+1) = f(a), you agree?

hushed vault
#

yeah sounds right

young spade
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knowing that our f(x) is 4 - x^2, you should be able to find a value of a that satisfies the equation.

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remembering that here, a is the value that determines the range [a,a+1]

hushed vault
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yeah

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okay perf

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sorry, oneee last question

young spade
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go ahead

hushed vault
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freak

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sorry hold on

young spade
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do a screenshot prob

hushed vault
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there ya go

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this is the one, i just dunno how to like, do this bro 😭 😭

young spade
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Ooh i was misreading this one and was banging my head so hard on it.

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Well

hushed vault
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PFFT

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me too bro me too 💔

young spade
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Well, first

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Any given polynomial of degree "n" has n roots too.

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Open to multiplicity

hushed vault
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yeah i'm ngl i don't understand

young spade
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Do you remember whats the multiplicity of a root?

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aka a "zero" of the function

hushed vault
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yeah, the power right?

young spade
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kind of

hushed vault
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the biggest power

young spade
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Nope, thats the degree of the polynomial

hushed vault
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whoops

young spade
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for example, x^4 - 4x^3 + 6x^2 - 4x + 1 is a degree 4 polynomial

hushed vault
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yeah cause 4 is the biggest power

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right?

young spade
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yeah

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There is a really important theorem literally called the Fundamental Theorem of Algebra

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I wont bore you with the full detail

hushed vault
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guys why did my teacher not teach me this 💔

young spade
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But the tl;dr is that a "n-degree" polynomial will have n amount of roots. > down to multiplicity

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So, here, this polynomial will have 4 roots.

hushed vault
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oh yeahh, i remember that, we just did not get the name or anything

young spade
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And just in case, the roots might be either real or complex.

hushed vault
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yeah cause -3i is one of the roots

young spade
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x = 1

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but this root has multiplicity 4

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thats because, if we factorize the polynomial, we get (x-1)^4

hushed vault
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ohhhh

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so its the power the root is to when factored down

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that makes alot more sense

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so it would be like (x-4)^2

young spade
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And you should remember that any n-degree polynomial can also be factorized into n-factors

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Now, we want a 4 degree polynomial, so we are missing two factors yet

hushed vault
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so 4 factors

young spade
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One of them is already given to us, -3i

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So we have:
$(x-4)^2(x+3i)(x-a)$ where a is our missing factor/root

woven radishBOT
young spade
#

You will agree that (x-4)^2 is entirely real.

hushed vault
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would the third factor not just be (x-3i)?

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ohh okay

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perfecto, thank you so much

young spade
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Yep, you appeal to diff of squares to argue that you get no complex coefficients

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depending on the problem, they will prob ask you to expand the factorization

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Which, yeah, takes a bit.

hushed vault
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alrighty, that twas my last question, tysm!

young spade
#

np, good luck

hushed vault
#

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limpid lance
#

This quesiton js tricky

devout snowBOT
limpid lance
#

For (c), I was able to obtain N11.9E however AI got a different answer

sand quarry
#

,rccw

woven radishBOT
crystal dawn
#

I'm not sure if I'm in the right headspace to understand this rn, but any time you have a discrepency with another source, please show the full working of both you and the source

sand quarry
#

This question has a lot of steps you need to take, so please do what Hanako said and show your working

devout snowBOT
#

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devout snowBOT
#

@limpid lance Has your question been resolved?

limpid lance
#

N12.9E sorry I forgot

#

AI’s answers

#

Let’s compute it cleanly and give the numerical bearing.


1. Resolve velocities into components

Take:

  • East = +x
  • North = +y

Athlete A: 3 m/s at N30°W

[
\vec v_A =
\begin{cases}
x_A = -3\sin30^\circ = -1.5
y_A = 3\cos30^\circ = 2.598
\end{cases}
]

Athlete B: 2 m/s at N10°E

[
\vec v_B =
\begin{cases}
x_B = 2\sin10^\circ = 0.347
y_B = 2\cos10^\circ = 1.970
\end{cases}
]


2. Relative velocity of B with respect to A

[
\vec v_{B/A} = \vec v_B - \vec v_A
]

[
\vec v_{B/A} =
\begin{cases}
x = 0.347 - (-1.5) = 1.847
y = 1.970 - 2.598 = -0.628
\end{cases}
]

So relative velocity points E and S.


3. Direction of separation at closest approach

At closest approach:
[
\vec r_{BA} \perp \vec v_{B/A}
]

Thus, the direction of (\vec r_{BA}) has slope:
[
\frac{y}{x} = -\frac{x_{v}}{y_{v}} = -\frac{1.847}{-0.628} = 2.94
]

So:
[
\tan\theta = \frac{x}{y} = \frac{1}{2.94}
\Rightarrow \theta \approx 18.8^\circ
]

This angle is measured from North towards East.


4. Direction athlete A must take to intercept B

Athlete A must run along the line joining A to B, i.e. along (\vec r_{BA}).

[
\boxed{\text{Direction} = \textbf{N }19^\circ\textbf{ E}}
]


✅ Final Answer

[
\boxed{\text{Athlete A should run in the direction } \textbf{N }19^\circ\textbf{ E}}
]

If you want, I can also show:

  • A labelled vector diagram, or
  • A short exam-marking version (3–4 lines).
woven radishBOT
#

S
Compile Error! Click the errors reaction for more information.
(You may edit your message to recompile.)

limpid lance
#

Different models keep getting different answers

#

Gemini got 11.9

limpid lance
devout snowBOT
#

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devout snowBOT
#

@limpid lance Has your question been resolved?

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young spade
#

I hope this helps.

#

And i also hope i read it correctly.

#

@limpid lance

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cinder tendon
#

Is this correct way to show? i havent done one in so long

lavish sigil
#

yep

cinder tendon
slate peak
lavish sigil
uneven coral
#

I write it more like a => than a ->, but oh well, I don't think it matters that much here

lavish sigil
#

,tex \begin{align*}
\int_0^2 (x + 1)^{-1/2}\dd{x} &= \int_1^3 u^{-1/2}\dd{u} \tag{$u = x + 1$} \
&= \frac{u^{1/2}}{1/2}\eval_1^3 = 2\sqrt{3} - 2 \approx 1.464
\end{align*}

#

Can TeXit not do align environments lol

woven radishBOT
#

jewels!

lavish sigil
#

(Looks better on a document)

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#

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cinder tendon
#

thanks

cinder tendon
#

.reopen sorry, i wrote it like this . i believe its correct now but just wanna double check

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placid cove
#

Why is the chain rule being used here? Am I misunderstanding theorem 2?

versed juniper
#

chain rule is always there

#

that's the du/dx

placid cove
#

Does it have something to do with the du/dx in part b? I get pretty lost with that notation

#

i see

uncut crow
#

the ‘u’ there is 2x^2 + 1

placid cove
#

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hard sable
#

not sure about

devout snowBOT
hard sable
#

aii

#

i know that p - 3x >= 0

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as graph is in the 1st quadrant

drifting sierra
#

Just plug in the point (3, 1/2)

hard sable
#

yeah so p - 9 >= 0, p >= 9

#

wait

#

you mean into the equation?

drifting sierra
#

Yes

hard sable
#

bruh i was overcomplicating it

#

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spiral burrow
devout snowBOT
spiral burrow
#

how can i find the coordinates of the red dot

native garnet
#

Are there any measurements or is this more of a proof?

spiral burrow
#

the radius is 50cm

#

wait i have some more

pseudo basin
#

!xy

devout snowBOT
#

Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.

spiral burrow
#

the angle that the y line makes with the blue line is 22,5

#

english is not my native language

pseudo basin
#

do not call me "bro".

willow helm
pseudo basin
#

also yeah it wasnt about language

#

it's that you gave us only pieces of the problem and not the full thing

#

can we have a picture of the full problem? we need to be sure you didn't miss anything else.

spiral burrow
#

im tryna design a centrifugal

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for a jet engine

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i have to put some weir angly things

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i need the cordinates to do that

native garnet
#

Did you find the problem in a textbook/worksheet?

spiral burrow
#

i tried to do it like this 300x=22,5.360

#

im kinda dumb

willow helm
#

What's 22,5.360

spiral burrow
#

i tried to do it like that if 360 degress equals to 300 whats 22,5 equals to

willow helm
#

uh

#

what?

spiral burrow
#

yeah i have to ask this to my teacher

willow helm
#

360 degrees equals 300

spiral burrow
#

3.2.50

willow helm
#

What's your language

spiral burrow
#

turkish

willow helm
#

Can you post everything in turkish

#

Because the translations don't do much good I am afraid

spiral burrow
#

çemberin yarıçapı 50cm ve kırmızı bir nokta var bu nokta bu çemberin 22,5 derecelik kısmına denk gelen şeklin ucunda yer alıyor pi sayısını 3 olarak alacağız kırmızı noktanın kordinatları lazım

native garnet
#

I tried redrawing the graph based on the information given.

willow helm
#

The radius of the circle is 50cm, and there is a red dot at the end of the shape that corresponds to the 22.5-degree part of this circle. We will assume the value of pi as 3. The coordinates of the red dot are needed. (I guess this is the translation)

#

||you lost me at assuming pi = 3 :(||

zinc flame
#

"assume the value of pi as 3" yup, definitely building a jet engine alright

spiral burrow
spiral burrow
zinc flame
#

I was joking, don't worry about it. anyway you're on the right track

native garnet
#

Yes, this feels like a geometry/trigonometry problem to me.

spiral burrow
spiral burrow
#

:(

#

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willow helm
#

have you learned about polar coordinates?

spiral burrow
#

.reopen

devout snowBOT
spiral burrow
#

i have to translate that

#

this thing?

willow helm
#

Yes

spiral burrow
#

imma go to sleep i just stole yall time sorry

#

not intentionaly

#

i swear

willow helm
#

No problem

#

good night

spiral burrow
#

thanks

#

im so sorry

#

please forgive me

willow helm
#

don't worry about it

spiral burrow
#

i mustve knew english before i came here

#

:(

#

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delicate fulcrum
#

I’m a second-year student at an Italian scientific high school.
Our math teacher gave our class this geometric riddle to solve. Almost nobody really tried to work it out, but I solved it using similar triangles.
At the end of the lesson, I showed my solution to the teacher, and he asked me how I managed to find the result without explicitly using the horizontal distance between P1 and P2.
The point is that I did use it implicitly, but it cancels out because of triangle similarity.
From similar triangles, I wrote:
x / 4 = (6 - x) / 6
Solving step by step:
6x = 4(6 - x)
6x = 24 - 4x
10x = 24
x = 2.4
At first I was confused because swapping the terms gives 6 - x = 3.6, but that is just the complementary height, not a different solution.
I believe the solution is correct, but I would really appreciate it if someone could confirm it and explain clearly why this method works.

versed juniper
#

the triangles arent similar though

#

they only share a side

#

nothing else

uneven coral
#

also the right angle (looks like it)

versed juniper
#

oh are you talking about the one formed by the person in the middle

delicate fulcrum
#

There is a right angle (as stated by the teacher), and the two triangles also share the angle at the intersection, so they have two equal angles and are therefore similar.

versed juniper
#

icwym

uneven coral
#

ahhhhhhh

#

do you mean the CP1O and DP2O triangle (O being his head)

versed juniper
#

those arent similar

uneven coral
#

yeah because the right angle is no longer present

#

but in any other triangle I don't see the equal angle at intersection

versed juniper
#

doing it algebraically with equations of the lines on a graph, the distance between the heights cancel out

delicate fulcrum
#

So, the only thing that wasn’t clear to me was why, if I swap the denominators, I get one value in one way, 2.4, and another value, 3.6, in the other way. And if I then subtract 3.6 from 6, I get 2.4. That’s the only thing I didn’t understand

uneven coral
#

ig what if we extend the 4 to 6, the connect it to D and extend x to that

#

maybe then geometrically it'd make some sense

delicate fulcrum
#

Here’s a photo of my calculations and how I tried to solve it

uneven coral
#

It's basically like if you extend the x to as high as 6

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and x could be either the x we have, or the 6 - x above it

#

then the value of x you'd get is 2.4 and 3.6, which would depend on which distance you found (the height of the man, or the extra distance above him till it's 6 metres)

delicate fulcrum
#

ooh ok so that’s how it is, i get it now, if this is the solution, thanks, didn’t get how the two proportions worked before, sorry if i stressed you out

uneven coral
#

IG it's almost like, the ratio between the 4 and the height of the man, is equal to the ratio between 6, and the height above that man till 6 metres

#

I can't exactly prove how though, although I do kinda see how that might work

delicate fulcrum
#

yeah i got that, actually i realized it right away when i saw the exercise, that’s why i did the proportion, it’s just that i didn’t understand why putting the denominator one way gave one result and swapping it gave another, thanks a lot

uneven coral
#

Ahhhh no problem man, happy to help

delicate fulcrum
#

Thanks !

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#

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visual stone
#

During a collision between two objects, momentum is conserved if there is no loss of energy. Thus pt = pAi + pBi = pAf + pBf , in which pt corresponds to the total momentum (in kg·m/s) and ( pAi, pBi, pAf, pBf) represent the initial and final momenta (in kg x m/s) of objets A and B. Even more, p = mv (p and v are vectors) in which p corresponds to the momentum (in kg x m/s) of an object, (m) its mass (in kg), and (v) its velocity (in m/s).

The diagram illustrates a curling throw, where stone A, with a mass of 18.8 kg, collides with stone B, with a mass of 17.5 kg.

What is the magnitude and direction of the velocity of stone A after the collision?

visual stone
#

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lusty igloo
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lusty igloo
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turbid imp
#

Super quick question, for euler's and fermat's theorem in discrete maths, is the y != 0 always, or just for positive whole numbers, etc.?

turbid imp
#

so as in, i don't know how to define y in it, should it be "y is a positive integer", y € N, y != 0, y € Z_+, or something else?

#

(and is it the same across both euler and fermat*)

vital edge
#

What exactly do you mean by Euler's and Fermat's theorems

#

There's too many of them

vagrant skiff
#

The most precise definition is y in Z and gcd(y,n)=1

#

or gcd(y,p) = 1 in Fermat’s

turbid imp
vital edge
#

Ah little theorem

#

You take a prime, and smth that the prime doesn't divide

#

Which, by the nature of primes, means that the gcd is 1 as cooly said

turbid imp
#

so y€Z?

vagrant skiff
#

So

#

glow$U_m = {, y in \Z_m \mid gcd(y,m) = 1,}$

#

That automatically excludes y = 0

vital edge
#

Why is your texit gay

#

How do I convert mine

vagrant skiff
#

Simply pay jet 100 bucks a day

woven radishBOT
#

クーリー

turbid imp
#

so can I just say y != 0 and then sgd(y,m)=1 => Y^phi(m) =_m 1? (where the = is actually the triple equalsign for kongruent)

#

wikipedia says "any integer a" (a is y in their case) for fermat's and for euler's "a positive integer"

#

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potent compass
devout snowBOT
potent compass
#

Please help

crystal dawn
#

combine the 2s in the numerator and denom separately first

#

have you tried this at least? ^

potent compass
#

Tysm

#

Is it always lien this though?

crystal dawn
#

wdym

potent compass
#

Uh Ig I get another question similar to this

#

Do I do the same thing

crystal dawn
#

I mean, yes? I don't see why not unless you wanna show the question

#

after all, all I see here is multiplication and division, and they are commutative

potent compass
#

Ty

potent compass
#

Can I multiply the final answer?

shut trail
#

powers are the same

#

so the bases can multiply

potent compass
#

Ohh tysm

#

Ty

#

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steep quartz
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steep quartz
#

is the teacher wrong or what

lunar harbor
#

,w increasing -x^3-3x^2+5

woven radishBOT
steep quartz
#

its increasing as long as x is negative

#

oh

#

bruh

#

wait i factored wrong

#

lol

#

mb

lunar harbor
steep quartz
#

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solid osprey
#

any ideas on how to find primes $p_1,p_2,p_3$ (not nessicarily distinct) such that
$$p_1+p_2+p_3+7=p_1p_2p_3$$

woven radishBOT
#

ihave<skissue>

solid osprey
#

i mean a cubic (RHS) should grow much faster than somethinng linear (LHS), but how can i formalize that idea?

hollow ice
#

parity seems more promising imo

solid osprey
#

mod 6? i tried that and it became pretty confusing

#

maybe im just bad

hollow ice
#

nahh

#

like 3 odd primes + 7 is even

#

but the product is odd

solid osprey
#

ohh

hollow ice
#

same with one 2 and 2 odds

solid osprey
#

so either all of them is 2 (fails) or one of them is 2

hollow ice
#

so that leaves you with 2x 2

solid osprey
#

wlog its p_3, so p_1+p_2+9=2p_1p_2

hollow ice
solid osprey
#

you will get sum+odd=product
odd+odd=even right?

hollow ice
#

odd = even is wrong

hollow ice
#

and even + odd is odd

solid osprey
#

ok im actually crazy

#

so we want 2 of them to be 2

hollow ice
#

yea

solid osprey
#

so p_1+4+7=4p_1
11/3=p_1

#

this isnt an integer, so no sols?

hollow ice
#

ig

#

yea

solid osprey
#

okay thank you!!

#

.solved

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#
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proven oriole
#

Trying to get good practice in, while I understand how to solve radical equations that are like. By themselves (an example being the square root of 19+X is equal to 1)

However when you combine two radicals I start to struggle. Here’s my work and truth be told I’m just a little uncertain if I’m even progressing the first step correctly

north roost
#

${(a+b)^2 \neq a^2 + b^2}$

woven radishBOT
north roost
#

js for simplification, id use u = 3-2x, maybe?

fossil locust
#

yeah, it would be easier to solve $\sqrt{2u + 1} + \sqrt u = 1$

woven radishBOT
proven oriole
#

How did you guys transform the problem into that

fossil locust
proven oriole
# woven radish **k**

and I'm assuming this is where I messed up originally? I did A^2+b^2 instead of (a+b)^2?

fossil locust
#

if you don't mind I'll list them out one by one

proven oriole
#

Also is u just filling in the variable for X?

fossil locust
#

then you want to get 7 - 4x in terms of u

proven oriole
restive river
#

hi is this the help channel for high school math?

fossil locust
fossil locust
devout snowBOT
restive river
fossil locust
restive river
proven oriole
#

i just realized i wrote the problem down wrong

#

okay okay and the reason I'm doing 1-square root of 3-2x is because thats the easiest thing to get rid of?

restive river
fossil locust
woven radishBOT
fossil locust
#

otherwise they won't learn anything

proven oriole
#

^^

#

South gets it

restive river
fossil locust
# woven radish **south**

think about what your middle term would be if you didn't rearrange it first

you'd get $2 \sqrt{7 - 4x} \sqrt{3 - 2x}$

woven radishBOT
restive river
proven oriole
#

i want it to be known that I'm still here, i'm just rewriting the problem and putting notes between each step. That way you can guys can not only see my work but track my thought process

restive river
proven oriole
#

okay wait, sorry. I'm looking at this problem of

steel sage
#

If you let y=3-2x, it becomes sqrt(y+1)+sqrt(y)=1. Furthermore you let y=(tan(t))^2 you will obtain (1+tan(t/2))^2=1-(tan(t/2))^2

restive river
#

did you forget the middle term while expanding (a+b)²?

steel sage
#

Maybe overcomplicated but first thing entered my mind

restive river
proven oriole
#

no

steel sage
#

Then forget what I said

proven oriole
#

and now theres like 3 people all saying a variety of things

restive river
north roost
#

r we serious...

restive river
steel sage
#

sqrt(1+2y), I was so dumb

proven oriole
# woven radish **south**

So if I put in this format. Not a lot changes in my head about how to attack the problem. It’s reorder but for what? Now I’ve done a similar problem where there was a number outside of the square root sign

steel sage
#

Anyway y=0 seems an obvious solution

proven oriole
#

Like this, and that’s how I handled it for the correct answer

#

So I’m a little lost on what the point of moving this one is supposed to be. And how I’m supposed to eliminate it

steel sage
fossil locust
fossil locust
fossil locust
#

if you have 2y - 1 = 3, then surely 2y = 4

#

the idea is to have one side be a constant

#

after $\sqrt[3] {2x + 6} = 4$, cubing both sides gives $2x + 6 = 64$ as you've written down

woven radishBOT
proven oriole
# woven radish **south**

right, i follow this. But why can't I just simply cube both sides for my original problem as well?

#

or does moving the 1 to the left, make me able to cube?

fossil locust
proven oriole
#

If you cube both sides then you cancel out the square roots. Which would take the problem from Sqrt of 7-4x + sq 3-2x=-1 down to

7-4x+ 3-2x=1

fossil locust
#

to undo cube roots, you cube both sides
to undo square roots, you square both sides

proven oriole
#

i'll write that down

north roost
#

\textbf{cubing} ${x}$' means you are doing ${x^3}$, whereas \textbf{squaring} ${x}$' means you are doing ${x^2}$

woven radishBOT
proven oriole
#

so in this case instead of cubing I'd be squaring both sides

#

so the problem would look like

#

Oh

north roost
#

,rccw

woven radishBOT
proven oriole
north roost
#

you must square

proven oriole
#

Sorry

north roost
#

gng

#

not cube

#

like this

proven oriole
#

Shit

#

Yeah

#

Yeah

#

My fault

#

I said it in my head and wrote down something diffe

north roost
#

${(\sqrt{7-4x})^2 = (1-\sqrt{3-2x})^2}$

woven radishBOT
north roost
#

this is what u envision, ya?

proven oriole
#

Mhm. In my head square is 2 because it’s 2 dimensional and cube is 3 because it’s 3

#

I just have to make sure I put the correct numbers when I do this

#

I apologize again for being slow to pick this up

rain summit
proven oriole
#

What is a domain restriction?

rain summit
#

Domain restriction of $\sqrt x$ is $x \geq 0$

woven radishBOT
#

1 divided by 0 equals Infinity

rain summit
#

Basically values that makes the function defined

restive river
# proven oriole so in this case instead of cubing I'd be squaring both sides

yes, here's a quick tip why. \textbf{squaring} ${x}$' means you are multiplying ${x}$ with itself, thus the exponential representation becomes ${x^2}$, the same way the square root of ${x}$ becomes ${x^(1/2)}$ and the CUBE root of x becomes ${x^(1/3)}$ so when you square ${x^(1/2)}$ exponentially the 1/2 is multiplied with 2, which gives 1 and you end up with ${x}$ which eases your expression by a 100!

woven radishBOT
#

smithereens

restive river
#

omg why won't it type 😭

steel sage
proven oriole
proven oriole
rain summit
woven radishBOT
#

1 divided by 0 equals Infinity

fossil locust
fossil locust
restive river
#

same goes for sqrt

proven oriole
#

I think I got it?

#

Also the notes on the bottom is for something entirely different ignore that

fossil locust
woven radishBOT
fossil locust
#

where's the middle term 2 * 1 * -sqrt(3 - 2x)

#

and why are you dividing everything by 2

restive river
proven oriole
# woven radish **k**

What’s the difference between these two functions? Because if (X+Y)^2
Don’t I have to take everything inside the parenthesis to the second power anyway?

woven radishBOT
#

smithereens

steel sage
#

7-4x=1+2(3-2x)

woven radishBOT
fossil locust
restive river
proven oriole
restive river
rain summit
#

Did he really squared the whole thing?

proven oriole
#

Going to erase and back up

restive river
#

@steel sage that's very smart 😭 I kinda need help with high school math these days, could I dm for help?

steel sage
#

Sure

restive river
woven radishBOT
#

smithereens

proven oriole
#

And I’m going to drag this question away from everything else for a moment

rain summit
restive river
restive river
rain summit
# restive river it's the same question tho

Still, someone's in a channel for an algebra question, and you are doing a trig one, i suggest opening a new channel and then linking your old convo into the new channel, or continue the convo there

steel sage
#

Sorry, you are right

restive river
proven oriole
#

That’s the part that’s messing with my brain

restive river
proven oriole
#

Uhm, gimme an example problem of binomial and binomial multiplication

#

I don’t know what that is by name alone

restive river
#

for eg
${(1+x)(2+x)}$ as such

woven radishBOT
#

smithereens

restive river
#

@proven oriole

fast garden
proven oriole
#

I’m answering it, so you can see how I’m going about tackling it

fossil locust
fossil locust
woven radishBOT
fossil locust
#

it's like how (1 + x) * 5 = 1 * 5 + x * 5

#

remember if you want to use FOIL, you should get 4 terms

#

well FOIL works cause of the distributive law

proven oriole
proven oriole
#

TEAH

proven oriole
#

OKAY

woven radishBOT
#

1 divided by 0 equals Infinity

restive river
proven oriole
#

Like I said I thought I was missing something with a X

woven radishBOT
#

smithereens

proven oriole
#

How does this multiplication thing tie into the division? Or the A^2+2ab+b^2

rain summit
#

simplifying in fractions

#

like how $\frac{(a + b)^2}{a + b} = a + b$

woven radishBOT
#

1 divided by 0 equals Infinity

rain summit
#

fractions are basically division

fossil locust
proven oriole
#

instead of doing A^2 +2AB+B^2
I could do A (A+B) + B(a+b)

In my case it would look like

rain summit
woven radishBOT
#

1 divided by 0 equals Infinity

restive river
woven radishBOT
#

smithereens

proven oriole
rain summit
#

expand further

proven oriole
#

Oh

fossil locust
#

7(7 - 4x) - 4x(7 - 4x)

restive river
#

@proven oriole are you understanding why we squared it?

proven oriole
#

I assume it’s -4x because the 4x is negative

#

And when I took it out for some reason I made it positive

restive river
#

hon idt you're grasping the basics of this

proven oriole
proven oriole
#

That I know

fossil locust
restive river
#

if you want to expand ${(7-4x)^2}$ then your first step is ${(7-4x)(7-4x)}$. tell me why.

woven radishBOT
#

smithereens

proven oriole
# woven radish **smithereens**

I need to do (7-4x) (7-4x) because that's that squaring is. I'm doing multiplying that equation twice. Is that answer too simple am I missing something?

restive river
# woven radish **south**

idt they're quite grasping the why behind it. you can't rely on a method to solve always if you don't know why you're using it in the first place

proven oriole
#

if i wanted to expand (7-4x)^5 I would do (7-4x) 5 times

restive river
woven radishBOT
#

smithereens

proven oriole
#

i'm not understanding what's being asked here. When I have two terms, what happens? What happens when what? What am I doing with the two terms? Two terms on their own don't mean a lot.

restive river
proven oriole
#

thats what i meant

#

sorry

restive river
woven radishBOT
#

smithereens

restive river
#

did you get my question

#

@proven oriole ?

#

which grade are you in btw

#

I'll have to leave in a few mins @proven oriole :((
@fossil locust take over

proven oriole
#

Yes, and I'm just solving the equation. I don't want you to think I don't know how to do things that I do know, because I struggle to word/explain math. Then if i show a picture of me doing the math you'll know if I understand or not.

#

and then I'd answer that equation

woven radishBOT
#

smithereens

restive river
#

the last term

proven oriole
#

OH

#

yep and i understand why it's squared

#

and i understand why its positive

#

i rushed

restive river
proven oriole
#

america?

restive river
#

ahh

#

the edu system is different here

#

12th is the last year

#

for us

#

idk how it works there lol

proven oriole
#

its the last year for highschool here too

restive river
#

what

#

and then you're off for college?

proven oriole
#

yeah..?

restive river
#

no more school years?

restive river
#

😭

#

that's the math we did in 6th grade here 😭

#

im in 10th rn

proven oriole
#

ok well

restive river
#

I can't find someone who's good with their stats :((

proven oriole
#

im happy you got it really early on, you can make fun of the dumb american sterotype in your off time. Please dont do it in front of my face

restive river
#

@fossil locust are you?

fossil locust
#

I don't want to be involved

restive river
fossil locust
proven oriole
#

alright, thank you for the help

#

how do you close?

deep abyss
#

.close

proven oriole
#

.close

devout snowBOT
#
Channel closed

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#
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flat willow
#

i have a quistion

how to divide (2x^3 - 4x^2 + 4) by (x-2)

pseudo basin
flat willow
#

yes

#

Y

pseudo basin
#

ok, what's troubling you with this one

winter torrent
#

start by writing it as 2x^3 - 4x^2 + 0x + 4

flat willow
#

i did that

winter torrent
#

$\polylongdiv[stage=1]{2x^3 - 4x^2 + 4}{x-2}$

woven radishBOT
#

two wuggen in a trenchcoat

flat willow
#

after the first step, 2X^3 is cancled, but -4X^2 is also cancled

winter torrent
#

sure

flat willow
#

im stuck here

pseudo basin
#

ok then just keep going

winter torrent
#

$\polylongdiv[stage=3]{2x^3 - 4x^2 + 4}{x-2}$

woven radishBOT
#

two wuggen in a trenchcoat

pseudo basin
#

your goal at each step is to kill the highest-degree term @flat willow

#

if more terms get killed, all the better, right?

#

you just move on to whichever one would be coming next

flat willow
pseudo basin
#

(well, except all that remains would be 4. and you're kinda just done)

pseudo basin
flat willow
pseudo basin
#

do what, exactly...?

#

all i did was explain how @winter torrent wrote down her first step of the polynomial division

#

which should result in much the same thing as what you did

flat willow
#

multiplying 2x^3 - 4x^2 by -1

rain summit
#

i tried in $\LaTeX$ testing but i can't do it

flat willow
winter torrent
#

well... we're subtracting it, which is the same as multiplying by -1 and then adding

#

it's just easier to read that way

pseudo basin
flat willow
#

but when we mulitiply 2x^2 by -2 we get -4X^2

-4X^2 - (-4X^2) = 0

pseudo basin
#

correct

devout snowBOT
#

@flat willow Has your question been resolved?

devout snowBOT
#
Channel closed

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#
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flat willow
devout snowBOT
#

@flat willow Has your question been resolved?

flat willow
#

yes

#

thank\

winter torrent
#

.close

devout snowBOT
#
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proven oriole
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I don’t understand where I’m supposed to go from here.

In case my hand writing isn’t clear enough. The problem is The square root of 8x+1 is equal to x+2

drifting sierra
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$\sqrt{8x+1} = x+2$, find x?

woven radishBOT
proven oriole
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Yes I’m trying to find X

proven oriole
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What does LHS Stand for?

drifting sierra
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From 7 to 8, you did -8x

sand pumice
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left hand side

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i mean on the left side of the = sign

drifting sierra
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8x - 8x is not x

proven oriole
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Gotcha

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Sorry in my head since “x” is undefined it might as well equal Zero. So I don’t ever remove X because it could be literally anything

drifting sierra
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That's not at all how you should think about it

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x is not undefined, it's unknown (for now)

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Saying it might as well equal zero is just incorrect

proven oriole
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What’s the difference between undefined and unknown, idk if that’s a dumb question

quartz spindle
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hii im new

drifting sierra
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1/0 is undefined

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So is 0/0, 0^0, or just "infinity"

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Those are not numbers

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x is a variable, it is supposed to have a value

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Now if the expression you're working on leads to x = 0/0 or something like that, you can conclude that x is undefined

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But before that, x is simply just unknown: you don't know its value

proven oriole
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Got it, I never had someone correct me on calling X that before

meager vale
proven oriole
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But I can see the difference between 1/0 which isn’t possible or infinity oppose to unknown

drifting sierra
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Right... first things first: your first step was squaring both sides, but that only keeps the equivalence if both sides have the same sign

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So before you do that step, you should at the very least state what range of value x can take

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You do know that sqrt(x) is only defined for x >= 0, right?

proven oriole
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I did not, no. So how would writing that down look like?

drifting sierra
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Writing what down exactly?

proven oriole
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This range thing

drifting sierra
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Just use words

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$\sqrt{x}$ is only defined for $x \ge 0$

woven radishBOT
drifting sierra
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That's perfectly fine to write

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Now in your case it's sqrt(8x+1), so for what range of values of x is that defined?

proven oriole
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Sorry I saw you typing and didn’t want to interrupt, but the square root of x must be greater than or equal to one in this case..? Is that a proper range? I don’t think it could be 8 because whatever X is must be multiplied by 8 but regardless of its outcome it will be added by one

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If it’s being added by one it can’t be zero

drifting sierra
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You're not quite thinking about it correctly

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Whatever is inside the sqrt must be greater than or equal to zero

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That means 8x+1 >= 0

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Can you solve this inequality?

proven oriole
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Oh, I overthought that

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But yes you can solve that

quartz spindle
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im in 10th grade and we have been taught about this

drifting sierra
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!nosols

devout snowBOT
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As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.

proven oriole
quartz spindle
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oh

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sorry i did not knew that

proven oriole
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It’s okay, you didn’t know lol

quartz spindle
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actually, you can square both sides and then use Discriminant formula

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use discriminant formula to further solve it

drifting sierra
quartz spindle
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btw in which grade do u study

proven oriole
quartz spindle
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what?

drifting sierra
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Ok but you should write the full thing

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By just saying -1/8 nobody knows whether you mean x = -1/8 or something else

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In this case it's x >= -1/8, right?

quartz spindle
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yo the value of x is either 3 or 1

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ig i am correct

drifting sierra
proven oriole
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Sorry, yes the statement
8x+1>=0 is untrue because X equals -1/8’s

drifting sierra
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No, that's still incorrect

quartz spindle
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what the heck is this server for?

proven oriole
drifting sierra
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Why are you saying "8x+1>=0 is untrue [...]"? That's not what solving means

proven oriole
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I don’t know what you mean by solving, I assumed you were asking me to break down the equation further. So I broke down 8x+1 then found out it couldn’t be right because if it simplifies to a negative it’s below zero

drifting sierra
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But 8x+1 >= 0 is clearly true if x is 2, for example

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Let's take a step back

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You are given the equation $\sqrt{8x+1} = x+2$, and asked to find its solutions, that is the set of values for x such that the equality holds

woven radishBOT
drifting sierra
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Let's try a few values for x and see what happens

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We'll try 0, 1, and -1

proven oriole
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I can do that, want me to write it out and show you how I do it?

drifting sierra
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Sure go ahead

proven oriole
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Awesome give me a moment as you gave me 3 numbers to punch in

quartz spindle
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Hello

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If you want then I can help you

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In simple way

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?

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Or I am going to sleep

proven oriole
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But I did it

proven oriole
quartz spindle
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What ur answer

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Tell

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Me

drifting sierra
proven oriole
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Yeah

drifting sierra
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The expression is sqrt(8x+1), not sqrt(8+x+1)

proven oriole
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Well im putting -1 in for x right?

drifting sierra
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8 and x are multiplied together

proven oriole
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Ohh that explains why I struggled to get a similar concept

drifting sierra
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This is very basic algebra, no wonder you're struggling with this exercise

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When you have an expression and you want to plug in a specific value for a variable, you need to think of it as replacing the variable with that value in parentheses

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So sqrt(8x+1) becomes sqrt(8(-1)+1)

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8 and -1 are still being multiplied

proven oriole
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I thought about that but second guessed it and decided to just go super literal. I’m a little rusty as I haven’t touched math in quite some time

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Just remembering a lot of rules to actually do things

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Okay I can do that though

drifting sierra
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Alright, try again

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You should know what to do with 0 too, now

proven oriole
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Yep

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Quick question sorry

proven oriole
drifting sierra
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Yes, the other side is (-1)+2, but here the parentheses are less useful

proven oriole
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Okay sorry for the pause

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Obviously the last one is also false

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Also to be super clear, I didn’t wanna take up too much paper space. So since it was real simple multiplication I then added the one each time

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Oh I forgot to put on the square root over them all

drifting sierra
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Ok but the sqrt disappeared

proven oriole
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Yeah I noticed that as I was staring at it

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The square root of 9 is 3

drifting sierra
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Also be careful what the sqrt contains, here it looks like the +1 is not included

proven oriole
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I’ll draw the lines thicker so I don’t confuse you or my future instructor

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My fault

drifting sierra
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Well it also doesn't help that the line is on top of the paper guide line

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Anyway, sqrt(9) does indeed equal 3

proven oriole
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Yeah, but uhm 1 is true 0 and -1 are not.

drifting sierra
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Right, for x=0 you get sqrt(1) which is just 1, but the other side is 2, so the equality does not hold

proven oriole
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I don’t want you to think I’m sassing you or nothin

drifting sierra
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You're missing fundamental knowledge so I'm trying to go over it quickly so that solving the actual exercise makes sense

proven oriole
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I appreciate that greatly

drifting sierra
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Now, when x = -1, can you tell me what happens?

proven oriole
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Idk how to word this

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It turns the 8 into a negative.

drifting sierra
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Yes, and you end up with sqrt(-7)

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What does this mean?

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Is sqrt(-7) something you can work with?

proven oriole
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No you can’t, there are no whole numbers that like square root to -7

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If that’s what you’re asking

drifting sierra
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Right

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So we say sqrt(-7) is undefined

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As soon as anything in an equation is undefined, you can stop and say the equation doesn't hold

proven oriole
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OHHH

drifting sierra
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That's where -1/8 comes in

proven oriole
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wait that’s so sick

drifting sierra
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sqrt(8x+1) is only defined when 8x+1 >= 0, so when x >= -1/8

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Do you understand that?

proven oriole
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Yes

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YES

drifting sierra
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Now you can start solving $\sqrt{8x+1} = x+2$

woven radishBOT
drifting sierra
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You can square both sides, but you must keep in mind that:

  • x >= -1/8, otherwise one side is undefined so the equation no longer holds
  • both sides must have the same sign (you can go back and check this later by plugging in your solutions into the original equation)
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For the second point, in this case, you can also just say that the left side is always >= 0 since it's a square root, and so x+2 must also be >= 0

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That means x >= -2

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But you already have x >= -1/8 so this other condition x >= -2 doesn't matter

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So far so good?

proven oriole
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Yep I’m following along

drifting sierra
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Then you tried to subtract 8x but did it wrong

proven oriole
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Because I said 8x-8x=x instead of 0
Or did I misunderstand 4x-8x?

drifting sierra
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The former, yes

lunar harbor
drifting sierra
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Hi

proven oriole
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Gotcha

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Gotcha gotcha gotcha

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But even when I do it properly and 0=x^2-4x+3

How would I break this down further?

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Wait actually

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I can take that 3 away

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Because it doesn’t have a X on it

drifting sierra
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No, you can't

proven oriole
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Dang it

drifting sierra
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If you do that you need to take 3 away from the 0 as well

proven oriole
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That was the plan

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Because when you do stuff like that it goes on both sides

drifting sierra
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So -3 = x^2 - 4x ?

proven oriole
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Mhm!

drifting sierra
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Ok but that doesn't really help

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This is the point where you need to know how to solve quadratic equations

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There are many ways to do that, one systematic way is simply to apply the quadratic formula

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Another way is to "complete the square"

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Yet another is to factorize, which is a lot easier when you already know one solution

proven oriole
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What’s the quadratic formula? Formula’s are pretty simple once you remember which one you need to attach to what

drifting sierra
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,, x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

woven radishBOT
proven oriole
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Okay wow

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Hm

drifting sierra
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For any equation ax^2 + bx + c = 0, this gives you the x values that satisfy it

proven oriole
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That’s a +- sign right? Meaning it can be either?

drifting sierra
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Yes, there are at most two solutions

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If the thing in the square root is negative, there are no solutions, if it's zero, there is exactly one, since the plus-or-minus doesn't matter

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If it's positive, then you get two, one for the plus, one for the minus

proven oriole
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Gotcha

drifting sierra
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That thing, b^2 - 4ac, is called the discriminant

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(it discriminates between the number of solutions: 0, 1, 2)

proven oriole
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So beforehand you gave me really
Simple questions for me to break down. Can you do the same with this quadractic equation? That way I know how to properly plug in numbers into it

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I can also then put it down on my note page of quadratic equations

drifting sierra
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Well you have x^2 - 4x + 3 = 0

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You need to identify what a, b, and c are

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Such that if you plug them back into ax^2 + bx + c = 0, you get your equation back

proven oriole
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Okay so

proven oriole
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Now if this formula makes any sort of sense. Then A B C is the exact order the numbers appear in. Which is also why it’s so important to rewrite my equation from left to right. Something I didn’t do until now lol

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Which makes me question is the X part in the A B C formula literally supposed to be X in the equation or am I missing something?

drifting sierra
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Yes it is

proven oriole
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So in that case

proven oriole
# woven radish **Nel**

Okay so that means in order to find X. I need to plug in the letters I just found into this here.

drifting sierra
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Yes

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Make sure your a,b,c values are correct

proven oriole
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Now before I go through the effort of painstakingly do the math. Do I need to convert numbers over as is? What I mean by that is:

for example. B for me is -4x. But according to the Quadratic formula B must be negative. Do I need to make my -4x positive since I’m mashing together two negatives? What if my B just so happened to be 4x? Would I make it negative to match the equation?

Secondary question. It messes with my brain when formulas do stuff like “4ac” or “2a” but thanks to you I know that when formulas put variables tightly together like that they need to be multiplied right? With paranthesis around them at that

drifting sierra
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Ok first of all, a,b,c do not contain x. They are the values you can plug into ax^2 + bx + c = 0 to get your equation x^2 - 4x + 3 = 0

proven oriole
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Oh that’s weird but I get it

drifting sierra
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If a was x^2 like you tried to do, you would get (x^2)x^2 + ... = 0, which is not the same as your equation x^2 + ... = 0

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Then, you say "b must be negative", but that's not the case at all

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Are you saying that just because the formula starts with "-b" ?

proven oriole
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Mhm

drifting sierra
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b can be any real number

proven oriole
drifting sierra
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-b is just that number, multiplied by -1

proven oriole
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So when plugging in -4, because I don’t bring down the X. I’d be doing -4*-1 to place it in that first slot

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That would make it a positive 4

drifting sierra
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Yes, if b = -4, then -b = -(-4) = 4

proven oriole
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Okay I’m getting it I’m getting it

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I can clean this up

proven oriole
drifting sierra
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You want ax^2 = x^2

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What value of a satisfies that?

proven oriole
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Typing out my thought process here
I want Ax^2 to =X^2
But x is unknown. My gut reaction says if I want something to not change I plug in 1 because 1 copies whatever it’s raised to or multiplied.

But 2 (which is 1^2) ≠ X^2

So I just put in X by itself and drop the exponent??

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Because X^2=x^2

drifting sierra
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But 2 (which is 1^2) ≠ X^2
Not sure what you mean

proven oriole
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Okay so I want Ax^2=X^2

If I plug in 1x^2

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Oh

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Sorry I think I’m just wrong

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I was going to say 1x^2 wouldn’t equal X^2

But I mistakingly did 1^2 instead of just leaving it at 1x^2

drifting sierra
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Right

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So a = 1

proven oriole
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Am I finally ready to solve this?

drifting sierra
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c = 0 ?

proven oriole
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How did I get there

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Whoops

drifting sierra
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Also, -4^2 is not the same as (-4)^2, careful

proven oriole
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Wow I need to parenthesis everything

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Okay yeah, i got that

drifting sierra
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For example you really don't need to write the (1) factors, since they don't change anything (in a product)

proven oriole
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I’ll get to that level after a few drills of solving radicals right now I gotta stay to the basics 💪

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Okay I’m not gonna send another picture of the same equation but! I did parenthesis every single thing I plugged in

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This is the easiest part, now I’m not trying to find out what I’m solving. Now I’m doing the fun part of actually solving lol

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If you add you get positive 3

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And subtract you get !

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1

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@drifting sierra holy hell. I got the answer right. Here’s my work for the addition the subtraction is on another page. (As you can see I ran out of space)

But! I want to say you were great

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And thank you so much for dedicating so much time to me. Not once did you make me feel bad about not knowing this or like stupid or anything

drifting sierra
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Good job catthumbsup

proven oriole
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Please have an amazing day i feel so pumped now

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.close