## Precalculus (10th Edition)

A graph of a rational function will have a hole if the function is undefined at a value in such a way that the function actually approaches the "value" of the hole. E.g. $f(x)=x\cdot \frac{x-1}{x-1}$ is basically $y=x$ apart from the hole at $x=1$ but the function approaches $y=1$ at the hole too.
A graph of a rational function will have a hole if the function is undefined at a value in such a way that the function actually approaches the "value" of the hole. E.g. $f(x)=x\cdot \frac{x-1}{x-1}$ is basically $y=x$ apart from the hole at $x=1$ but the function approaches $y=1$ at the hole too.