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1. E v ~(D v C)
2. (E v ~D) -> C / :. E
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3. E v (~D & ~C) 1 De Morgan's Law
4. (E v ~D) & (E v ~C) 3 Distribution
5. (E v ~C) & (E v ~D) 4 Commutation
6. E v ~D 4 Simplification
7. C 2,6 Modus Ponens
8. E v ~C 5 Simplification
9. ~C v E 8 Commutation
10. C -> E 9 Material Implication
11. E 10,7 Modus Ponens