Question

look at this table:
x | y
0 | 18
12 | 11
7 | 19
is this relation a function?
yes no

Explanation:

Step1: Recall function definition

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

Step2: Check unique x-values

The $x$-values are 0, 12, 7. All are distinct, so each maps to only one $y$-value.

Answer:

yes