SOLUTION: Andrew factored the expression -4x^3+2x^2+8x as -2x(4x^2-2x-8). But when Melissa applied the distributive law and multiplied out -2x(4x^2-2x-8), she got -8x^3+4x^2+16x; thus, Andre

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Andrew factored the expression -4x^3+2x^2+8x as -2x(4x^2-2x-8). But when Melissa applied the distributive law and multiplied out -2x(4x^2-2x-8), she got -8x^3+4x^2+16x; thus, Andre      Log On

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Question 630637: Andrew factored the expression -4x^3+2x^2+8x as -2x(4x^2-2x-8). But when Melissa applied the distributive law and multiplied out -2x(4x^2-2x-8), she got -8x^3+4x^2+16x; thus, Andrew's solution does not appear to check. Why is this?
Please help Andrew to understand this better. EXPLAIN YOUR REASONING and correctly factor the orginal expression, if possible. If the expression is prime, so state.
I have worked on this and I am totally messed up. Can you help?
Thanks in advance...
Found 2 solutions by dfrazzetto, stanbon:
Answer by dfrazzetto(283) About Me  (Show Source):
You can put this solution on YOUR website!
Just some arithmetic errors:
-4x^3+2x^2+8x
(-2x)(2x^2 -x -4)
CHeck, multiply it back out
(-2x)(2x^2 -x -4) = -4x^3 - (2x^2) - (-8x) = -4x^3+2x^2+8x
Correct

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
-4x^3+2x^2+8x
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= -2x(2x^2 -x - 4)
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Cheers,
Stan H.
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