Question

On a coordinate plane, solid circles appear at the following points: (negative 5, negative 3), (negative 4, negative 4), (negative 2, 2), (1, 3), (1, negative 2), (2, 1), (5, negative 4).
Which ordered pair can be removed so that the resulting graph represents a function?

(–2, 2)
(1, 3)
(5, –4)
(–4, –4)

Answer 1

(1, 3)

Reason: a relation is a function if each x-value has only one y-value. The x-value 1 appears twice, at (1, 3) and (1, −2); removing (1, 3) leaves only one y for x = 1, so the set is a function.