Question

what is $f^{-1}(9)$?

x f(x)
4 9
9 14
15 18
17 23
21 27
23 32

Explanation:

Step1: Recall inverse function definition

For $f^{-1}(y)=x$, find $x$ where $f(x)=y$.

Step2: Locate $f(x)=9$ in table

Find row with $f(x)=9$: $x=4$ when $f(x)=9$.

Answer:

4