Question

look at this table:
x | y
5 | 13
20 | 15
7 | 17
5 | 6
12 | 16
-3 | 11
is this relation a function?
yes no

Explanation:

A relation is a function if each input (x-value) has exactly one output (y-value). Here, the x-value 5 maps to two different y-values: 13 and 6.

Answer:

no