SOLUTION: Please help me factor completely 2x^4 + 4x^3 - 8x^2 - 16x I have a final tomorrow and I�m trying to review, not sure if I did it right.

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Question 1106785: Please help me factor completely 2x^4 + 4x^3 - 8x^2 - 16x
I have a final tomorrow and I�m trying to review, not sure if I did it right.
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52767) (Show Source):
You can put this solution on YOUR website!
.

2x^4 + 4x^3 - 8x^2 - 16x = apply grouping = = (2x^4 + 4x^3) - (8x^2+16x) = 2x^3*(x+2) - 8x(x+2) = (x+2)*(2x^3-8x) = (x+2)*2x*(x^2-4) = 2x*(x+2)*(x+2)*(x-2) = .

Answer by josgarithmetic(39615) (Show Source):
You can put this solution on YOUR website!

Try breaking the cubic by dividing it by either (x+2) or by (x-2).

synthetic division:

2 | 1 2 -4 -8 | | 2 8 8 |--------------------------- 1 4 4 0

This means two factors of the cubic are x-2 and x^2+4x+4.

That quadratic factor is (x+2)(x+2).

The complete factorization is .