(27 points) True/False Questions - To get credit, you must give brief reasons for each answer T F The statement "1 2-4" is a valid proposition. T F The proposition qvpdpq) is a tautology T F ax (P(x) Q(x) (x P(x)) A (Ex Q(x) T F For any two sets A, B, we have A-B = AnB T F The logical expression 3x (P(X) (Ply) proposition y*x)) represents a valid