#I dont understand shi--

144 messages · Page 1 of 1 (latest)

alpine matrix
rough foxBOT
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dry mauve
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Firstly we want to factor it

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Do you know how to do that

alpine matrix
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No I dont know how to do that

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😦

unreal flower
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😭

dry mauve
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Do you know what difference of squares is

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Basically

alpine matrix
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now how did this happen

unreal flower
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Put $ at the front too

alpine matrix
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oh my god what was i doing

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my entire life

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can you please elaborate

dry mauve
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$x^2 - 1$ can be factored as $(x-1)$$(x+1)$

thorn berryBOT
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CaliforniaJumpingBean

dry mauve
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Do you see that

alpine matrix
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yeah

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but how did this happen

dry mauve
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Wdym how

alpine matrix
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where did the x-1 and x+1 came from

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i dont know how to factor

dry mauve
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So the first term is x^2, the middle term is 0x, and the last term is -1

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So the middle is canceled

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Therefore we have factors that are the same, except for the opposite sign

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And since the last term is -1

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We know the factors are -1 and 1

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Idk

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Do you get that?

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We can also factor the bottom similarly

alpine matrix
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wait

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let me process this

alpine matrix
dry mauve
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Since the last term is -1 right

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So in this method

alpine matrix
dry mauve
alpine matrix
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sorry for my low iq actually i am not a math student

dry mauve
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-1 and 1

dry mauve
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So

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Basically

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We look at the first term for x

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It is a singular x

alpine matrix
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yeah

dry mauve
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So the only choices for the coefficients are 1 and 1 right

alpine matrix
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yeah

dry mauve
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(x+a)(x+b) where a and b are unknown as of this step

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Ok

alpine matrix
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aight

dry mauve
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So we have no middle term right

alpine matrix
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yeah

dry mauve
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And the last term is -1

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So there is only 1 combination of a and b that works

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-1 and 1

alpine matrix
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ohh

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another question

unreal flower
alpine matrix
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why we use two signs - and + why not negative or positive both sides

unreal flower
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it's the bottom part that you should factor

unreal flower
thorn berryBOT
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Anonymous

alpine matrix
unreal flower
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just try and distribute and you can convince yourself this always holds true

dry mauve
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Or grouping

unreal flower
alpine matrix
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ik that

unreal flower
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but the idea for factor $x^2-7x+12$ is you find two numbers whose product is 12 and sum is -7

thorn berryBOT
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Anonymous

alpine matrix
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x = -b+- root b^2*4ac/2a

dry mauve
alpine matrix
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let me do it

alpine matrix
unreal flower
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try and think about it first

unreal flower
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i mean you can but this is much faster

alpine matrix
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okay

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wait

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let me factor it myself

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tell me if i am wrong

dry mauve
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Good luck with this problem

dry mauve
alpine matrix
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understood

dry mauve
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I think 2 of us isn't helpful

alpine matrix
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(x-3)(x+4)

unreal flower
unreal flower
alpine matrix
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1

unreal flower
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well that's not -7

alpine matrix
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oh

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wait

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(x-3)(x-4)

unreal flower
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perfect

alpine matrix
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less go

unreal flower
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here's how I'd approach this problem:

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$\frac{x^2-1}{x^2-7x+12} \ge 1$ \
$\frac{x^2-1}{x^2-7x+12}-\frac{x^2-7x+12}{x^2-7x+12}\ge 0$ \
$\frac{7x-13}{(x-4)(x-3)}\ge 0$

alpine matrix
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huh

thorn berryBOT
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Anonymous

unreal flower
# alpine matrix huh

I subtracted 1 from both sides and got a common denominator so that i can add the fractions

alpine matrix
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so did you cross multiply denominator with 1 to get it common

unreal flower
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you just want the bottom part to be the same

alpine matrix
unreal flower
alpine matrix
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wow

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are we allowed to do that

unreal flower
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well notice, what is $\frac{x^2-7x+12}{x^2-7x+12}$ equal to? the same number divided by itself

thorn berryBOT
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Anonymous

alpine matrix
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yeah

unreal flower
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well, what is it?

alpine matrix
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1 ?

unreal flower
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yes, so it's the exact same as before

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just a different way of writing it

alpine matrix
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which way do you prefer

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i think that one was easier

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for me

unreal flower
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yes but you can't add the fractions if the bottom term isn't the same

unreal flower
alpine matrix
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should i use the wavy curve method to further solve this ?

unreal flower
alpine matrix
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waa--

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aight

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ty for ur time sir

alpine matrix
unreal flower
alpine matrix
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oh cmon

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make me understand

unreal flower
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if you want to, sure

alpine matrix
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i dont want to waste time on long methods

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but please elaborate while explaing cuz i am just dumb

unreal flower
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dash lines means negative, bold lines means positive

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if you are familiar with the quadratic and linear functions,
(x-4)(x-3): you know that it's negative in between the roots and positive everywhere else
(7x-13): the line is positive for anything above its root (13/7) and negative everywhere below it
multiply the signs of both regions, and you get your desired result

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it's like the same process of how people normally do it, except if you understand the functions well enough you don't need to plug anything into your calculator

tiny coral
# alpine matrix

bring one to this side, make it into a single fraction, create factors, check od powered factors for their zeroes and plot it on number line using wavy curve

unreal flower
alpine matrix
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thanks for explaining it was really helpfull ^^