An equation (or graph) is only a function if, for every x-value, there is on and only one corresponding y-value. To tell if a graph is a function, we can use the vertical line test. In other words, if vertical line corssing the graph at any point were to touch more than one point, we would be able to determine that the graph is not a function. The graph that is given to us has two vertical lines already (at what appears to be x = 6 and x = -6). If we were to draw vertical lines that go through x = 6, we could see that the graph does not pass the vertical line test. For the two x values, there are several y values that satisfy the equation represented by the graph.
Therefore, the answer is False, since the graph is not a function