Let p, q, r denote primitive statements.
(a) Use truth tables to verify the following logical equivalences.
(i) p → (q ∧ r) ⇔ (p → q) ∧ (p → r)
(ii) [(p ∨ q) → r] ⇔ [(p → r) ∧ (q → r)]
(iii) [p → (q ∨ r)] ⇔ [¬r → (p → q)]
(b) Use the substitution rules to show that
[p → (q ∨ r)] [(p ∧ ¬q) → r].