Answer
$y$ is not a function of $x$.
Work Step by Step
RECALL:
If all vertical lines pass through the graph one time at the most, then the graph represents $y$ as a function of $x$.
Notice that a number of vertical lines (such as $x=0$) will pass through the graph at more than one point.
Thus, the given graph does not represent $y$ as a function of $x$.
