Answer
$f^{-1}(-4)=-4$
Work Step by Step
RECALL:
(1) If $(a, b)$ is on the graph of $f(x)$, then $f(a) = b$.
(2) If $f(a)=b$, then $f^{-1}(b)=a$
The given graph contains $(-4, -4)$
This means that $f(-4) = -4$.
Thus, $f^{-1}(-4)=-4$.