Explain why it is or isn’t.

Question

{(4, -2), (4, -4), (1, 2), (1, 5), (1, -4)}

Answer 1

This set of points is not a function because there are multiple y-values assigned to the same x-values. In particular, the x-value 4 is associated with both y=-2 and y=-4, and the x-value 1 is associated with y=2, y=5, and y=-4. In a function, each x-value should only correspond to one y-value.