Question

Sort the graphs according to whether or not "y" is a function of "x"

Answer 1

Answer is
* the graph on the left is NOT a function, it does not pass the vertical line test.
* The graph on the right IS a function, it passes the vertical line test and it has only one x value for every y value.

Reason - with a graph you can use the vertical line test without knowing any of the coordinates. See the attachment. If a vertical line touches two or more lines it is not a function.

Answer 2

The first graph, (the one by the left is not a function)

The second graph (the one by the right is a function)