Dados os conjuntos $A = {2, 3, 5, 6, 7, 9}$, $B = {2, 3, 6, 7, 9, 10, 12}$, $C = {2, 4, 5, 8, 9, 10, 11}$ e $D = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}$.. a-) $(A cup B) cap C$. b-) $(A cup ...