Question

Which graph shows a set of ordered pairs that represent a function?

On a coordinate plane, solid circles appear at the following points: (negative 2, 3), (negative 1, 2), (1, 1), (2, negative 1), (2, negative 3), (4, negative 5).

On a coordinate plane, solid circles appear at the following points: (negative 4, negative 4), (negative 2, 2), (1, 1), (2, negative 5), (4, negative 3), (4, 4).

On a coordinate plane, solid circles appear at the following points: (negative 3, 2), (negative 2, 2), (0, 1), (1, 3), (2, negative 4), (4, negative 1).

On a coordinate plane, solid circles appear at the following points: (negative 4, 2), (negative 2, 1), (negative 2, negative 1), (0, negative 2), (0, negative 4), (2, negative 5).

Answer 1

The third graph. Its x-values are all different: -3, -2, 0, 1, 2, 4, so each input has exactly one output. The others are not functions because they repeat x-values with different y-values (graph 1: x=2; graph 2: x=4; graph 4: x=-2 and x=0).