SOLUTION: 1. (Q∨R)→(W∨U) 2. W→P 3. Q∙T 4. U→Z 5. S→M 6. S∨~Y 7. (P∨Z)→~M ∴ ~Y 8. Q 3, simp 9.

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Question 277572: 1. (Q∨R)→(W∨U)
2. W→P
3. Q∙T
4. U→Z
5. S→M
6. S∨~Y
7. (P∨Z)→~M ∴ ~Y
8. Q 3, simp
9. Q∨R 8, ADD
10. W∨U 1,9 MP
11. P∨S 10,2,4 CD
(I have completed lines 8-11 myself, but I cannot get past that. Thanks.)

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
You made a mistake on line 11. You should have P v Z (not P v S) since the consequent of U -> Z is Z


So continuing with your work... 

11.  P v Z                     2,4,10      Constructive Dilemma
12.  ~M                        7,11        Modus Ponens
13.  ~S                        5,12        Modus Tollens
14.  ~Y                        6,13        Disjunctive Syllogism


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