Composite and inverse functions

The idea

$fg(x)$ means do $g$ first, then $f$. The inverse $f^{-1}(x)$ undoes $f$: write $y = f(x)$, rearrange for $x$, then swap the letters.

1. For $fg(x)$, substitute $g(x)$ into $f$ wherever there is an $x$.
2. For $f^{-1}(x)$, write $y = f(x)$ and make $x$ the subject.
3. Replace $y$ with $x$ in your answer.

Watch out $fg(x)$ is not $f(x) \times g(x)$, and $g$ goes first.