1. F v (G & S) 2. ~ (I v S) // F & F 3. (F v G) & (F v S) 1, Distribution 4. (F v S) & (F v G) 3, Commutation 5. F v S 4, Simplification 6. ~I & ~S 2, DeMorgan's law 7. ~S & ~I 6, Commutation 8. ~S 7, Simplification 9. S v F 5, Commutation 10. F 8, Disjunctive Syllogism 11. F & F 10,10, Conjunction Edwin