I have 3 tasks to solve, and I believe that I've achieved correct answer, but I might be totally wrong.

The question is if these expressions are correct or incorrect (true/false)

a) C -> (A -> B) |= -C ^ (-A v B)

b) C -> A( -> B) |= -C v -A v B

c) -C v (-A v B) |= C->(A->B)

I'd appreciate your help, and solutions for these tasks.

/David.T