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Living_dreams
prove the following set equality is valid if and only if sets A and B are disjoint. ( A U B) - B = A
Suppose that A and B are joint. |dw:1360843065418:dw| If you remove B, you'll end up with something like a cresent and not something like A. That's the idea, now it's up to you to write it in a more formal way. Hint: \[A\cup B = A + B - ??\]