Question 196020
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1.  A v (~B v ~C)
2.  A -> (D -> E) 
3.  ~(~B v ~D)            :. C -> (D -> E) 
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4.  A v ~(~~B & ~~C)                    1    De Morgan's Law
5.  A v ~(B & C)                        4    Double Negation
6.  ~(B & C) v A                        5    Commutation
7.  (B & C) -> A                        6    Material Implication
8.  B -> (C -> A)                       7    Exportation
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9. ~~B & ~~D                            3    De Morgan's Law
10. B & D                               9    Double Negation
11. B                                  10    Simplification
12. C -> A                           8,11    Modus Ponens
13. C -> (D -> E)                    12,2    Hypothetical Syllogism
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