Answer
$-5$
Work Step by Step
By the definition of an inverse one-to-one function, if $g(x)=y$, then we have $g^{-1} (y)=x$.
Since $g(x)$ is a one-to-one function, then for each $x$ there must be a unique $g(x)$ and all the $g(x)$ values will be distinct.
Therefore, when $g(-5)=3 $, then its inverse can be expressed as: $g^{-1} (3) =-5$
In other words, when finding the inverse of a function, the $x$ and $y$ values get switched.
