Question

Which relation is a function?

Answer 1

To be a function all the x s must be different. D

Answer 2

In a function, for every x, there can only be one y result. There can be multiple x values for a y, however. Lets go over the answer choices:

X A.) (1, 2) and (1, 5) have the same x values, but different y values.

X B.) All the given coordinates have an x of 1, but they all give different results.

X C.) (2, 3) and (2, 5) have the same x values, but different y values.

√ D.) Even though all the y values are the same, the x values are all different, so it is a function.

Therefore, D is the only answer choice that represents a function.

Hope this helps! :)