I dont really know how to do this question..mainly were to start.

Here it is exactly..

Just as the difference rule gives rise to a formula for the probability of the complement of an event, so the addition and inclusion/exclusion rules give rise to formulas for the probability of the union of mutually disjoint events and for a general union of (not necessarily mutually exclusive) events.

a. Prove that for mutually disjoint events A and B.

P(A U B) = P(A) + P(B)

b. Prove that for any events A and B

P(A U B) = P(A) + P(B) - P(A ∩ B)

These are just practice questions outta my book but it doesnt provide solutions for them. Can someone help me out please?

Thanks.