Hey there!
In order to see if it's a function or not, it can't have the same x value twice, or it just has to pass the vertical line test.
This means that you could put a vertical line anywhere and it would not pass between two points.
If we look, we could indeed try the vertical line test, and and there would be no intersection between two points.
Additionally, we also do not have any repeating x values on this quadratic function's parabola.
Hope this helps!
