(x^3 + x + 21) divided by (x+3) | Mathematics | Page 1

torn blade Nov 10, 2022, 9:27 AM

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Use long division to solve this

drifting topaz Nov 10, 2022, 9:30 AM

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Have u covered long division of polynomials?

torn blade Nov 10, 2022, 9:30 AM

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Yes

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But this one have like a “x” in the way

drifting topaz Nov 10, 2022, 9:31 AM

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I’ll do it and send it cause idk how to explain this kinda thing in words

torn blade Nov 10, 2022, 9:31 AM

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idk why there’s a random 6x

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Literally

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Ohhh wait

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I did it

drifting topaz Nov 10, 2022, 9:33 AM

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torn blade Nov 10, 2022, 9:33 AM

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What did u do there

drifting topaz Nov 10, 2022, 9:33 AM

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Long division

torn blade Nov 10, 2022, 9:33 AM

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I do it in one big chuck

drifting topaz Nov 10, 2022, 9:34 AM

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Yea that’s nasty

torn blade Nov 10, 2022, 9:34 AM

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I figured out what I was doing wrong

drifting topaz Nov 10, 2022, 9:34 AM

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Did u get same answer as me?

torn blade Nov 10, 2022, 9:34 AM

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I made it 0x^2

torn blade Nov 10, 2022, 9:34 AM

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drifting topaz Did u get same answer as me?

Yea

drifting topaz Nov 10, 2022, 9:34 AM

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Nice

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@torn blade u think u could help me?

torn blade Nov 10, 2022, 9:35 AM

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With

drifting topaz Nov 10, 2022, 9:36 AM

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It was binomial expansion but done it now

torn blade Nov 10, 2022, 9:37 AM

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I’m confused again

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💀

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@drifting topaz

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You wanna help me again

drifting topaz Nov 10, 2022, 9:42 AM

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Sure lmao

bronze lantern Nov 10, 2022, 9:43 AM

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you can use Horners' method too

torn blade Nov 10, 2022, 9:43 AM

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Idk somehow someone explain to me

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Why is this so weird to calculate

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3c

drifting topaz Nov 10, 2022, 9:43 AM

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That looks pretty easy

torn blade Nov 10, 2022, 9:43 AM

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@bronze lantern what’s that

bronze lantern Nov 10, 2022, 9:44 AM

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torn blade

oh

torn blade Nov 10, 2022, 9:44 AM

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bronze lantern oh

?

bronze lantern Nov 10, 2022, 9:45 AM

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torn blade ?

they asked you to use long division

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I thought you can use any technique

torn blade Nov 10, 2022, 9:45 AM

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Anyway

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Could you help me do it

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Idk how this works

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I did the normal king division questions and they were fine

drifting topaz Nov 10, 2022, 9:47 AM

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I’ll try it in a sec

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torn blade Nov 10, 2022, 9:51 AM

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Ur working out doesn’t make sense

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Wtf

hot ingot Nov 10, 2022, 9:53 AM

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,w (4x^4 - 3x^2 - 5)/(x - 1) long division

grand novaBOT Nov 10, 2022, 9:53 AM

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hot ingot Nov 10, 2022, 9:53 AM

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torn blade Ur working out doesn’t make sense

Why not

torn blade Nov 10, 2022, 9:53 AM

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Idk

hot ingot Nov 10, 2022, 9:54 AM

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It is right tho

torn blade Nov 10, 2022, 9:54 AM

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It doesn’t make sense to me

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Explain to me

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What he did

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I under 4x^3

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But how tf did he get 4x^2

drifting topaz Nov 10, 2022, 9:56 AM

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So because

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I had (4x^4 - 3x^2 - 5) - (4x^4 - 4x^3)

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So the x^4 terms cancelled out

torn blade Nov 10, 2022, 9:57 AM

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Wtf do u mean u had those

drifting topaz Nov 10, 2022, 9:57 AM

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So I then had -3x^2 - 5 + 4x^3

torn blade Nov 10, 2022, 9:57 AM

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what what

drifting topaz Nov 10, 2022, 9:58 AM

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So in long division

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You divide the first term by x

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Then you times the result by x and the other value

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And it’s always take away

hot ingot Nov 10, 2022, 9:59 AM

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Do you maybe get it like this?

torn blade Nov 10, 2022, 11:40 AM

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Got it

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But now confused with factorising

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@drifting topaz you still here?

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@hot ingot

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@bronze lantern

drifting topaz Nov 10, 2022, 11:40 AM

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What’s up

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@torn blade

torn blade Nov 10, 2022, 11:43 AM

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How do you factorise

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Ngl I just forgot

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and never done soemthing with 3 numbers

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Only quadratic factorising

drifting topaz Nov 10, 2022, 11:43 AM

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What are u factorising

torn blade Nov 10, 2022, 11:44 AM

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Steps please

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Not the answer

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bc it’s x^3 has to be in 3 brackets

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(x-+?) (x+-?) (x+-?)

drifting topaz Nov 10, 2022, 11:46 AM

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This isn’t factorising just a quick question
If you’ve got a calculator can u just put -6 into that rq

torn blade Nov 10, 2022, 11:48 AM

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Why -6

drifting topaz Nov 10, 2022, 11:48 AM

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@torn blade

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Just checking something

torn blade Nov 10, 2022, 11:48 AM

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they want me to factorise tho

drifting topaz Nov 10, 2022, 11:48 AM

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Yes I’m

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Ik

torn blade Nov 10, 2022, 11:50 AM

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uh

drifting topaz Nov 10, 2022, 11:52 AM

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Ok I was just checking something

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But whatever I said before isn’t relevant to factorising

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And idk how you’d factor a cubic

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@torn blade what year r u?

torn blade Nov 10, 2022, 11:55 AM

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drifting topaz <@456226577798135808> what year r u?

10

drifting topaz Nov 10, 2022, 11:55 AM

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Ok

torn blade Nov 10, 2022, 12:00 PM

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drifting topaz But whatever I said before isn’t relevant to factorising

Oh ur right

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We have to solve it

drifting topaz Nov 10, 2022, 12:00 PM

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Wym

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We have to solve it

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You could use factor theorem

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f(x) = cubic equation
Sub in values 1,2,3 -1,-2,-3

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then if it is = 0

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x = that value so (x - value) is one of the brackets

torn blade Nov 10, 2022, 12:03 PM

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It’s x-1

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@drifting topaz

drifting topaz Nov 10, 2022, 12:04 PM

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Now you can use long division

torn blade Nov 10, 2022, 12:04 PM

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I did

drifting topaz Nov 10, 2022, 12:04 PM

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So you have all the answers?

torn blade Nov 10, 2022, 12:04 PM

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Only one

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X-1

drifting topaz Nov 10, 2022, 12:05 PM

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Show me your working

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x - 1 is a factor

torn blade Nov 10, 2022, 12:05 PM

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quotient is x^2 + 7x + 10

drifting topaz Nov 10, 2022, 12:05 PM

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Ok and you should know how to factorise that

torn blade Nov 10, 2022, 12:05 PM

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drifting topaz Ok and you should know how to factorise that

Ohhh your right

drifting topaz Nov 10, 2022, 12:06 PM

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But can I still see your working rq? U have me slightly confused

torn blade Nov 10, 2022, 12:06 PM

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It’s x+5

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x+2

drifting topaz Nov 10, 2022, 12:06 PM

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Ye

torn blade Nov 10, 2022, 12:06 PM

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And x-1

drifting topaz Nov 10, 2022, 12:06 PM

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Ok so how did u know x-1 is a factor

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By putting 1 in the equation?

torn blade Nov 10, 2022, 12:06 PM

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Substituting

drifting topaz Nov 10, 2022, 12:06 PM

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Ok

torn blade Nov 10, 2022, 12:06 PM

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I just tried

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x+1

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x+2

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x-1

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x-2

drifting topaz Nov 10, 2022, 12:07 PM

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You should write that down

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Something like f(1) =

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The cubic with the x values replaced by 1

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To show that it’s a factor

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@torn blade where r u from btw?

torn blade Nov 10, 2022, 12:48 PM

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Aus

earnest gull Nov 10, 2022, 3:36 PM

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Hey, this is the solution to the problem

X³+X+21 ÷ x+3

eternal rapids Nov 10, 2022, 4:04 PM

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horners method is much easier

drifting topaz Nov 10, 2022, 4:06 PM

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What is horners method

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@eternal rapids

#(x^3 + x + 21) divided by (x+3)