Answer
The given relation does not represent $y$ as a function of $x$.
domain: $(-\infty, +\infty)$
range: $[0, +\infty)$
Work Step by Step
RECALL: Vertical Line Test
If all vertical lines will pass through the graph of a relation in at most one point only, then the relation defines $y$ as a function of $x$.
To know if the given graph represents $y$ as a function of $x$, perform the vertical line test.
Note that the vertical line $x=3$ passes through the given graph at an infinite number of points. This means that the graph fails the vertical line test.
Thus, the given relation does not represent $y$ as a function of $x$.
The graph covers all x-values so the domain is $(-\infty, +\infty)$.
The y-values are greater than or equal to zero so the range is $[0, +\infty)$.
