Question

Which set of ordered pairs represents a function?

{(9,8), (-1,7),(-1, –9), (3, -1)}
{(9,-5), (4,6), (9,8),(-6,9)}
{(-8,0), (-8,2), (5,–7), (-2, -9)}
{(2,9), (-4,-6), (9,6), (0,6)}​

Answer 1

D

Explanation:

An input value in a function can only have one output value.

It cannot be A, because input -1 has two outputs.

It cannot be B, because input 9 has two outputs.

It cannot be C, because input -8 has two outputs.

Therefore, it must be D.