F(x)=(2x+3)(x-2) and g(x)=2x2-16. find g(x)-f(x)

G(x) - f(x) = -x - 10

First, simplify f(x).
(2x+3)*(x-2) = 2x^2 + x - 16

Next, subtract.

    2x^2       - 16
-   2x^2 + x -   6

              - x - 10

The answer is -x -10    assuming that g(x) is 2x^2 - 6