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0
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4
avatar+454 

The teacher has written an equation of the form \(p(x)=0\) on the board, where \(p(x)\)is a quadratic, but Heather can't read the linear term. She can see that the quadratic term is \(4x^2\) and that the constant is \(-24\). She asks her neighbor, Noel, what the linear term is.

Noel decides to tease her and just says, ``One of the roots is 4.''

Heather then says, ``Oh, thanks!''

She then correctly writes down the linear term. What was the linear term? Write the entire term, not just the coefficient.

 

The answer is NOT 0

 Nov 30, 2022
edited by Keihaku  Nov 30, 2022
 #1
avatar
-1

Let p(x) = (Ax + B)(Cx + D).  Then expanding, we get p(x) = ACx^2 + (AD + BC)x + BD, so AC = 4, BC = -24.

 

Also, x = 4 is a root, so B = 4A.

 

Solving this system, we get A = 1, B = 4, C = 4, D = -6, so the constant term is (AD + BC) x = (-6 + 16)x = 10x.

 Nov 30, 2022
 #2
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That wasn't right, sorry. Can someone else pls help?

Keihaku  Nov 30, 2022
 #3
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-2

Okay let me see

 Nov 30, 2022
 #4
avatar+115 
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Oh.. Guest was off by just a little....

 

The answer is -10x, not 10x!

It was 4x^2 - 10x - 24!

IF you are curious to see how i got the quadratic and the steps, just ask

 

I suggest you try to learn something from this problem, so you should ask someone, or me about the solutioin

 Nov 30, 2022
edited by Imcool  Nov 30, 2022

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