Question

F(x)=8−4x−x^3 g(x)=x^2+7x−9 Find f(x)+g(x).

Answer 1

The question requires us to add the two functions. 
F(x)=8−4x−x³
g(x)=x²+7x−9

F(x)+g(x) = (8−4x−x³)+(x²+7x−9)
                =8-9+7x-4x+x²-x³
                = -1+3x+x²-x³

                =x²-x³+3x-1