Question

Why is this not a function? Please add explanation. Thank you!

Answer 1

there are two of the same x-values (1) and for something to be a function x cannot repeat.

Explanation:

Answer 2

There are two different y-values assigned to the same x-value.

Explanation:

A function may not have two y-values assigned to the same x-value.

(1,7) and (1,-1) have two different y-values (7 and -1) assigned to the same x-value (1).