I've managed to do 3(a), it is false. I used the counter example: A= a, B= b, C = a, b.
How do I do 3(b)? 3(b) is 3(a) reversed.
I'm pretty sure 3(b) is true since the RHS will always end up being 'larger', but i don't know how to go about proving it.
EDIT: ignore my reasoning in the OP, I...
how do I go about doing 3(a) and 3(b)?
I'm guessing that for 3(a), it is true, since we have for LHS:
P((A or B) and C)
we can consider the case P(A and C) by excluding B, and this is a subset of the RHS when we also exclude B: (P(A) and P(C)).
We can consider excluding B because...