Answer
The inverse of the function $f(x)$ decreases on $(f(0),f(5))$.
Work Step by Step
If a function $f(x)$ is one-to-one, then for all $y=f(x)$, there is only one $x$. This means that the domain of the function $f(x)$ becomes the range of the inverse function and the range of the inverse function $f^{-1}(x)$ becomes the domain of the inverse function.
We are told that $f(x)$ is decreasing on $(0,5)$. Thus we know that it will pass the horizontal line test and will be a one-to-one function with an inverse. We also know that the inverse, $f^{-1}(x)$, is decreasing on $(f(0),f(5))$.
