Question

Which relation is a function?


A.
{(1, 2); (2, 5); (3, 2); (4, 5)}


B.
{(1, 2); (1, 3); (3, 2); (4, 2)}


C.
{(1, 2); (2, 3); (3, 4); (2, 5)}


D.
{(1, 2); (2, 3); (3, 4); (1, 5)}

Answer 1

D

Answer 2

In a function, you can't have two ordered pairs with the same x-coordinate.
In other words, if you see an x-coordinate used more than once, it is not a function.

Answer 3

The answer is not D, btw.