Question 1104861
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1. A -> (B -> C)
2. A -> B
3. ~C ->(A V D)  / C V D

              | 4. ~(C V D)        AIP
              | 5. ~C & ~D       4, DM
              | 6. ~C            5, Simp
              | 7. A V D       3,6, MP
              | 8. ~D & ~C       5, Comm
              | 9. ~D            8, Simp
              |10. D V A         7, Comm
              |11. A          10,9, DS
              |12. B          2,12, MP
              |13. B -> C     1,13, MP
              |14. C         13,12, MP
              |15. C & ~C     14,6, Conj
16. C V D                          4-15 IP

Edwin</pre></font></b>