SOLUTION: please help me solve: 1.D v (S & I) 2.D>S :. S

The word is "prove", not "solve"

1. D v (S & I)
2. D > S         :. S

       |3. ~S      Assumption for Indirect Proof
       |4. ~D      2,3, Modus Tollens
       |5. S & I   1,4, Disjunctive Syllogism    
       |6. S       5, Simplification 
       |7. S & ~S  6,3, Conjunction

8. S    3-7 Indirect Proof



Edwin