SOLUTION: 1. A ⊃ B 2. C ⊃ D 3. ~(D v B) // C ≡ A

Question 1188618:
1. A ⊃ B
2. C ⊃ D
3. ~(D v B) // C ≡ A

Answer by Edwin McCravy(20054) (Show Source): You can put this solution on YOUR website!

1.	A ⊃ B
2.	C ⊃ D
3.	~(D ∨ B) // C ≡ A

4.      ~D • ~B            3, DeMorgan's law
5.      ~D                 4, simpification
6.      ~C                 2,5, modus tollens
7.      ~C ∨ A             6, addition
8.       C ⊃ A             7, material implication
9.      ~B • ~D            4, commutation
10.     ~B                 9, simplification
11.     ~A                 1,10, modus tollens
12.     ~A ∨ C             11, addition
13.      A ⊃ C             12, material implication
14,      C ≡ A             8,13, material equivalence 

Edwin

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