3. 4, 5. Please prove by Contradiction that ((pq) (qr)) ((rs) (s->t) )s always true Please build a Tuth table to prove that p->(-p->q) is always true Please prove by Contradiction that ((pq) (-r-q))-)(-TA-5) -p ) always true 3. 4, 5. Please prove by Contradiction that ((pq) (qr)) ((rs) (s->t) )s always true Please build a Tuth table to prove that p->(-p->q) is always true Please prove by Contradiction that ((pq) (-r-q))-)(-TA-5) -p ) always true