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anonymous
 4 years ago
Solving a quadratic  like equation... I am totally confused! Here is the problem: (x^2 + 4x)^2  (x^2 + 4x)  20=0. It says let A = X^2 + 4x, then A^2  A  20 =0. Then they factored it (A5)(A+4) = 0 I understand how they factor it, but I do not understand how they got from step one to step two. Someone help me? Where did the A^2  A  20 = 0 come from?
anonymous
 4 years ago
Solving a quadratic  like equation... I am totally confused! Here is the problem: (x^2 + 4x)^2  (x^2 + 4x)  20=0. It says let A = X^2 + 4x, then A^2  A  20 =0. Then they factored it (A5)(A+4) = 0 I understand how they factor it, but I do not understand how they got from step one to step two. Someone help me? Where did the A^2  A  20 = 0 come from?

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Hero
 4 years ago
Best ResponseYou've already chosen the best response.2(x^2 + 4x)^2  (x^2 + 4x)  20=0 ( A )^2  ( A )  20=0

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Well, when you take (x^2 +4x)=A You do see that the question is (x^2 + 4x)^2  (x^2 + 4x)  20 =0 right? So just replace (x^2 +4x) with A, we get A^2  A +20 =0 Then factorize it, as (A+4)(A5) = 0 and you're all set. :)

Hero
 4 years ago
Best ResponseYou've already chosen the best response.2Anywhere you see x^2 + 4x, replace it with A

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0oooooh duh!! Ok, that totally helps now. I don't know why I wasn't seeing that before.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0thank you, that cleared up so much confusion and frustration!
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