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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 4x2 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
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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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Okay let me see

 Nov 30, 2022
 #4
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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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