Consider the following sets: a = {84n23 | n e z}, в 3 (12п — 1| пе z}, an с [14п + 9|n€ z). a) show that a is a proper subset of b b) show that a is a proper subset of c c) show that there is no containment relation between b and c

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.