1. The problem statement, all variables and given/known data Prove or find counterexamples. For any sets A, B, C in a universe U: if A union C contained B union C then A contained B 2. Relevant equations none. 3. The attempt at a solution im just not sure if i did it right. id appreciate if you can check my work and let me know what changes i have to make. thanks Let A be the empty set, and let B = C Then A union C = B and B union C = B so, A union C contains B union C, but A does not contain B because A is the empty set and B is not.