Answer
(a) $f^{-1}(18)=5$
(b) $f(2)=4$
Work Step by Step
(a) We are given: $f(5)=18$. We know that the inverse of a one-to-one function has the $x$ and $y$ values switched, so: $f^{-1}(18)=5$.
(b) We are given: $f^{-1}(4)=2$. We know that the inverse of a one-to-one function has the $x$ and $y$ values switched, so: $f(2)=4$.
