Inverse function of fractional Polynom

Question

Let $P$ and $Q$ two polynomial function of degre $n$,

and $f$ defined by $f(x)=\frac{P(x)}{Q(x)}$ such that $f$ is stricte monotone on an interval $I$ of $\mathbb{R}$

how we can compute the inverse of $f$ on $I$ ?

Thanks in advance