Question

look at this table:

x	y
13	20
0	-10
0	-15

is this relation a function?
yes
no

Explanation:

Step1: Recall the definition of a function

A function is a relation where each input ($x$-value) has exactly one output ($y$-value).

Step2: Check the $x$-values in the table

In the given table, the $x$-value $0$ has two different $y$-values: $- 10$ and $-15$.

Answer:

no