1. ∼F → ∼G 2. P → ∼Q 3. ∼F ∨ P 4. (∼G ∨ ∼Q) → (L • M) ∴ L | 5. ~L Assumption for indirect proof | 6. ~L ∨ ~M 5, addition | 7. ~(L • M) 6, deMorgan's law | 8. ~(~G ∨ ~Q) 4,7, modus tollens | 9. ~~G • ~~Q 8, deMorgan's law |10. G • Q 9, double negation |11. Q • G 10, commutation |12. Q 11, simplification |13. ~~Q 12, double negation |14. ~P 2,13, modus tollens |15. P ∨ ~F 3, commutation |16. ~F 15,14, disjunctive syllogism |17. ~G 1,16, modus ponens |18. G 10, simplification |19. G • ~G 18,17, conjunction 20. L lines 5-19 indirect proof Edwin