# Question: use a formal proof to show that p q...

###### Question details

Use a formal proof to show that (p ∨ q) ∧ (¬p ∨ q) ∧ (p ∨ ¬q) ∧ (¬p ∨ ¬q) leads to a contradiction Prove that if a | b ^ c | d, ac | bd. Prove that if a ≡ b (mod m) ^ c ≡ d (mod m), then ac ≡ bd (mod m) |