I having problems with these two questions. I know that both deals the DeMorgan's law but dont know what to do.
First of all, does mean all elements in that are not in ? If so, then there are two things to point out: the first equality is wrong, it should read
( on the leftt side, not )
and both of them are the actual statement of De Morgan's laws for sets. So, is your question: how do you prove De Morgan's laws?