Question

Use the vertical line test to determine if the relation {(–6,–2), (–2, 6), (0, 3), (3, 5)} is a function. Explain your response.

Answer 1

First, graph each point on the coordinate plane.
Now think of a vertical line moving from left to right. The line is always vertical. It starts at the left of the graph and moves to the right. If at any time, the line intersects more than one point, then the relation is not a function. If all the x-coordinates are different, the vertical line cannot touch more than one point at a time.