Question

Write the following set in set-builder (Rule Method) form :

$B_6$ = { ....., -6, -3, 0, 3, 6, ..... }

Answer 1

Since the set has all multiples of $3$ including positive and negative ones which are obtained by multiplying $3$ with all integers,
$B_6=$ {$x:x=3n,nϵZ$ }