Question

look at this table;

x	y
3	1
3	17
-17	3
0	-12
13	1

is this relation a function?

Explanation:

Step1: Recall function definition

A relation is a function if each input $x$ has exactly one output $y$.

Step2: Check $x$-values for repeats

Look at the $x$-value 3: it maps to $y=1$ and $y=17$.

Answer:

no