please i need help with an assignment due soon

Is ((p - 9) 1 -P) - -9 a tautology? Answer YES" or NO" and justify your answer. You may use a truth table to justify your answer.Is the following a valid argument? Answer ' YES" or ' 'NO" and justify your answer. Either sales or expenses will go up. If sales go up, then the boss will be happy. If expenses go up, then the boss will be unhappy. Therefore, sales and expenses will not both go up.Prove that (-9 A P) - ( -P 1 9) is logically equivalent to p - q by applying a chain of logical identities