Question 1157893
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 1.  (E v F) ⊃ (C • D)
 2.  (D v G) ⊃ H 
 3.  E v G               /H

                  | 4. ~H          Assumption for Indirect Proof
                  | 5. ~(D v G)    2,4, Modus Tollens
                  | 6. ~D • ~G     5, DeMorgan's Law  
                  | 7. ~D          6, Simplification
                  | 8. ~D v ~C     7, Addition
                  | 9. ~(D • C)    8, DeMorgan's Law
                  |10. ~(C • D)    9, Commutation
                  |11. ~(E v F)    1,10, Modus Tollens
                  |12. ~E • ~F     11, DeMorgan's Law
                  |13. ~E          12, Simplification
                  |14. G           3,13 Disjunctive Syllogism
                  |15. ~G • ~D     6, Commutation
                  |16. ~G          15, Simplification
                  |17. G • ~G      14,16, Conjunction
18.  H                   Lines 4-17   Indirect Proof

Edwin</pre>