Andrew factored the expression 28x^3-42x^2+35x as 7x(4x^2+6x-5). But when Melissa applied the distributive law and multiplied out 7x(4x^2+6x-5) , she got 28x^3+42x^2-35x ; 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.

Question

Andrew factored the expression 28x^3-42x^2+35x as 7x(4x^2+6x-5). But when Melissa applied the distributive law and multiplied out 7x(4x^2+6x-5) , she got 28x^3+42x^2-35x ; 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.
 
Can someone please help me with this question.

Julie · Answer

The negative sign is misplaced, and must go before the 6x instead of the 5, making the correct factor: 7x(4x^2-6x+5)

3 days · Answer

because Andrews is wrong