Look at the picture.
Domain:
![x\in(-\infty,\ -2]\ \cup\ [2,\ \infty)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2mnhwkb720w0rgoegxyfzyxsbmqxr3ssp8.png)

Range:


all real numbers
A function is a relationship that links every x element of an X set to a single y element of another Y set.
The relation is not a function because for all values of x from domain except -2 and 2 we have two values of y.