Question

Which set of ordered pairs represents a function?

{(2, –2), (1, 5), (–2, 2), (1, –3), (8, –1)}
{(3, –1), (7, 1), (–6, –1), (9, 1), (2, –1)}
{(6, 8), (5, 2), (–2, –5), (1, –3), (–2, 9)}
{(–3, 1), (6, 3), (–3, 2), (–3, –3), (1, –1)}

Answer 1

By definition, a function can only have 1 y-value for any given x-value. This means that no x-value should be repeated in a set of ordered pairs.

The first set has 2 x-values of 1.
The second set has no repetitions.
The third set has 2 values of x = -2.
The fourth set has 3 values of x = -3.

Therefore, only the second set represents a function.