2. Wyznacz zbiory AUB, AUC, BUC, AU BUC dla: a) A = (2,3), B = {1,2,8), C = {2,3,5), b) A = {2}, B = (2,5), C = (2,5,7), c) A = {1,8), B = (4), C = (3,4,7).​