I want to ask how to prove question 9? and why proving a subset would be enough if the proof has it. 9. Using the notation of the previous problem, prove that for sets A, B, C, DE P(X) AAB = CAD → AAC...

I want to ask how to prove question 9? and why proving a subset would be enough if the proof has it.

Extracted text: 9. Using the notation of the previous problem, prove that for sets A, B, C, DE P(X) AAB = CAD → AAC = BAD.


Extracted text: 8. Given sets A, B E P(X), their symmetric difference is defined by AAB = (A – B) U(B – A) = (AU B) – (An B).