Question

Use set builder notation to give a description of this set {0,3,6,9,12}

Answer 1

Let us use set builder notation to give a description of the set $A=\{0,3,6,9,12\}:$

$A=\{n\in\Z\ | \ 3\text{ divides }n\text{ and }0\le n\le 12\}.$