Yes.
Both are good counterexamples.
Conclude that A=B if A,B, and C are sets such that?
(a) A U C= B U C
(b) A ∩ C = B ∩ C
a) No.
Becasue if A = {0}, B = {1} and C = {0,1}. Then A U C= B U C
but A <> B
(b) No.
Since A = {0}, B = {1} and C = {2}. Then A ∩ C = B ∩ C but A <> B
Would this be correct?