SOLUTION: I.Use an ordinary proof (not conditional or indirect) to solve the following arguments. ~N ⊃ (~R ⊃ C) R ⊃ N ~C /N Thank you!

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Question 1157890: I.Use an ordinary proof (not conditional or indirect) to solve the following arguments.
~N ⊃ (~R ⊃ C)
R ⊃ N
~C /N

Thank you!
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
I.Use an ordinary proof (not conditional or indirect) to solve the following arguments.
 1.  ~N ⊃ (~R ⊃ C)
 2.  R ⊃ N
 3.  ~C                /N 
 
 4. (~N ● ~R) ⊃ C        1, Importation
 5. ~C ⊃ ~(~N ● ~R)      4, Transposition
 6. ~C ⊃ (~~N v ~~R)     5, DeMorgan's law
 7. ~C ⊃ (N v R)         6, Double Negation
 8. N v R                7,3, Modus Ponens
 9. R v N                8, Commutation
10. ~~R v N              9, Double Negation
11. ~R ⊃ N              10, Material Implication
12. R v ~R               Tautology
13. N v N                2,11,12, Constructive Dilemma 
14. N                    13, Tautology

Edwin