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| Question 1144033:  Construct a formal proof of validity for the following argument
 ~B v [(C⊃D) · (E⊃D)]
 B · (C v E)
 Therefore, D
 Answer by math_helper(2461)
      (Show Source): 
You can put this solution on YOUR website! Construct a formal proof of validity for the following argument ~B v [(C⊃D) · (E⊃D)]
 B · (C v E)
 Therefore, D
 
 -------------------
 NOTE: Using
 & for "AND"
 v for "OR"
 --> for  "implies"
 -------------------
 1. ~B v ((C-->D) & (E-->D))  Premise
 2. B & (C v E)               Premise
 3. B                         2 Simplification (SIMP)
 4. ((C-->D) & (E-->D))       3,1 Conditional Disjunction (CD)
 5. C v E                     2 SIMP
 6. :: C                      Conditional Proof (CP) assumption #1
 7. :: D                      6,4 Modus Ponens (MP)
 8. :: E                      CP assumption #2
 9. :: D                      8,4 MP
 10.:: (C V E) --> D          6-9 Proof by Cases (PBC)
 11. D                        5,6-10  CP
 
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