Look at the picture.
Domain:
[tex]x\in(-\infty,\ -2]\ \cup\ [2,\ \infty)[/tex]
[tex]x\leq-2\ \vee\ x\geq2[/tex]
Range:
[tex]y\in(-\infty,\ \infty)[/tex]
[tex]y\in\mathbb{R}[/tex]
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.
