7. Determine if the following expressions are tautologies, contradictions, or contingencies by using truth tables. You may not use the logical equivalences to (7.5 marks) simplify the expressions and you must show all your work. 8. Determine if the following expression is a tautology, a contradiction, or a contingency by using the logical equivalences. You may not use a truth. Show all your work, labelling each rule used, and do not skip any steps.2.5 marks)