No, it is not a function. It fails the vertical line test (VLT). VLT state that if you draw a vertical line, it must only intersect the graph one time. If it intersections more than once, then it is not a function.
No because it fails the vertical line test. Note that a vertical line can be drawn through the graph which passes through 2 points. If it was a function any vertical line would pass through only one point on the graph.
