(x²-3x+4) - (x³ +7x-2)
= x²-3x+4-x³+7x-2
In this step, they took the equations out of the parenthesis. In order to do that, you must use the distributive property. In the second equation -(x³+7x-2), everything within the parenthesis should be multiplied by the negative. Here would be the correct answer:
=x²-3x+4-x³-7x+2
