Question

Which relation is a function?

O {{7, 12), (1, -5), (3, -10), (2, -5)}
O {(-3, 4), (-2, 5), (0, 9), (0, 12)}
{(1, 2), (1, 5), (1, -1), (1, 4)}
{(8, -1), (2, -1), (3, 8), (2,5}

Answer 1

The first one because X does not repeat

Answer 2

The first one: {{7, 12), (1, -5), (3, -10), (2, -5)}

Explanation:

Functions can't have repeating x values. Each x has to have its own y value.