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 -8x3 + 4x2 + 16x; thus, Andrew’s solution does not appear to check. Why is that? Please help Andrew to understand this better. Explain your reasoning and correctly factor the original expression, if possible. If the expression is prime, so state.
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Notice that Andrew made a mistake. When you remove the factor -2x from -4x^3, the first term is 2x^2, not 4x^2 as Andrew wrote.
Similarly, when you factor the second term 2x^2, the factors are -2x and -x, not -2x as Andrew wrote.
When you factor the third term 8x, the factors are -2x and -4, not -8 as Andres wrote.
-2x ( 2x*x -x -4 )
Similarly, when you factor the second term 2x^2, the factors are -2x and -x, not -2x as Andrew wrote.
When you factor the third term 8x, the factors are -2x and -4, not -8 as Andres wrote.
-2x ( 2x*x -x -4 )
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It was factored wrong.
4x^3+2x^2+8x = 2x[ 2x^2 + x + 4 ]
Rather than favoring out 2 x, only x was factored out in the other solution.
4x^3+2x^2+8x = 2x[ 2x^2 + x + 4 ]
Rather than favoring out 2 x, only x was factored out in the other solution.
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-4x^3+2x^2+8x = -2x(2x^2-x-4)
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It should be -2x(2x^2 - x - 4)