## Calculus (3rd Edition)

$$G'(2)= -18.$$
Given $G(x)=f(g(x))$, then we have $G'(x)=f'(g(x))g'(x)$ and hence $$G'(2)=f'(g(2))g'(2)=f'(4)g'(2)=-2(9)=-18.$$