1. N>(F&A) 2. B>(R&F) /(NvB)>(A&R) 3. (NvB)>(F&A) 1, addition 4. (BvN)>(R&F) 2, addition 5. (NvB)>(R&F) 4, commutation 6. (NvB)>[(F&A)&(R&F)] 3,5, composition 7. (NvB)>[(A&F)&(R&F)] 6, commutation 8. (NvB)>(A&F) 7, simplification 9. (NvB)>[(R&F)&(A&F)] 7, commutation 10. (NvB)>(R&F) 9, simplification 11. (NvB)>A 8, simplification 12. (NvB)>R 10, simplification 13. (NvB)>(A&R) 11,12, composition [Your teacher may allow you to skip some of those commutation steps.] Edwin