Answer:
4
Step-by-step explanation:
[tex] \because \: f(4) = 2 \\ \therefore \: {f}^{ - 1} (f(4)) = {f}^{ - 1} (2) \\ \therefore \: 4 = {f}^{ - 1} (2) \\ \huge \red{ \boxed{{f}^{ - 1} (2) = 4}}[/tex]
4 four
hope it helps you
