1. B∨~C 2. B→E 3. ~~C ∴ ~B∨E ----------------- 4. ~C ∨ B 1, Commutation 5. B 4,3 Disjuntive Syllogism 6. E 2,5 Modus Ponens 7. E ∨ ~B 6, Addition 8. ~B ∨ E 7 Commutation