To find if a graph is a function you can use the vertical line test. The vertical line test is where you place a vertical (up and down) line on the graph. If this vertical line intersects the graph more then once it is NOT a function. It is a relation. Below I attached an image taking the vertical line test of this graph.
As you can see the vertical line intersect the graphed line at all points. This means this is a relation, not a function
Hope this helped!
~Just a girl in love with Shawn Mendes
