Andrew factored the expression28x^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. If the expression is prime, so state.

Question

Andrew factored the expression28x^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. If the expression is prime, so state.

anonymous · Answer

28x^3-42x^2+35
=7x(4x^2-6x+5)

Andrew factored correctly,but he made mistake in signs in the bracket. its -6x and +5 , and not +6x and   -5