$f(3) = 9$

Because $f(x)$ is even, $f(-3) = f(3) =$ part $a =$ _____

Since $f(x)$ and $g(x)$ are inverse functions for $x ≥ 0$, $g(9) = f(3) =$______________

Plug in your answer from part (a).

Recall that $f(x)$ and $g(x)$ are inverse functions for $x ≥ 0$, and the definition of an inverse function: $f(g(x)) = x$.

Refer to the hint in part (e).