17. Contrapositive: can fly. exercise 18-19, use be Morgan's laws to write the given for the following statement: It is not true that birds and pigs 18. An Equivalent statement 19. Negation Use a truth table to determine whether the two statements are equivalent. 20. ~ (p - 9 ), ~p 1 ~ q p q p-q ~ (p = q) TT TF FT F F p q P - q b~ v d~ T T TF FT F F