Given that $f(x)$ is a function such that $f(1)=2$, $f(4)=3$, $f(7)=4$, and $f^{-1}(x)$ is the inverse of $f(x)$, what is $f^{-1}(f^{-1}(3))$?

Work from the inside out: first find the inverse of 3 and then find the inverse of that answer.

Since f(4) = 3, f^{-1}(3) = 4

Since f(7) = 4, f^{-1}(4) = 7.