This section is truly overkill for any test we might have. But read the instructions anyway. One way to prove is to demonstrate that truth table match. However, as the problems get larger, the truth table method becomes gnarlier. So, use of any of properties of Boolean variables or, perhaps Boolean Algebra Identies, might be the best way to go. What's the best way to disprove? A counterexample! Quick and dirty, no one can argue.