#### Answer

The curve is not a function of $x$.

#### Work Step by Step

RECALL:
The Vertical Line Test states that if all vertical lines will pass through a graph in at most one point, then the graph represents a function of $x$.
Note that most vertical lines (e.g., $x=0$, $x=-1$, $x=1$, etc.) that will pass through the graph at two different points.
The graph fails the vertical line test.
Thus, the curve does not represent a function of $x$.