1. The problem statement, all variables and given/known data 1. Suppose A-B is equivalent to B-A. show that A is equivalent to B. 2. if A,B and C are nonempty and A cross B is equivalent to A cross C then B is equivalent to C Any help would be appreciated, thanks! 3. The attempt at a solution I tried constructing a bijection, but that did not work out right. Any ideas?