1. A → (B → C) 2. ~A ∨ (B → C) 1, Material implication 3. ~A ∨ (~B ∨ C) 2, Material implication 4. (~A ∨ ~B) ∨ C 3, Association 5. ~(A & B) ∨ C 4, deMorgan's law 6. (A & B) → C 5, Material implication 7. (B & A) → C 6, Commutation Edwin