I have 2 problems that are annoying the heck out of me...

#1. If A is contained in B prove that (C\B) is contained in (C\A) Either prove the converse is true or give a counterexample. Don't even know where to start. It is only the first week of the course, so I just need pretty basic help.

#2. Under what conditions does A\(A\B)=B. Again, how do I start this?