Question

Let U = {3, 6, 9, 12, 15, 18, 21, 24} and A = {9, 12, 15, 21}. Find A'.

Answer 1

this is the answer
A'={3,6,18,24}

Answer 2

Heya!

U = {3, 6, 9, 12, 15, 18, 21, 24}
A = {9, 12, 15, 21}
A' = {3,6,18,24}

A' include all those terms which aren't in Universal set.