Question 1010732
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1. X > Y 
2. (Y v ~X) > (Y > Z)       
 / ~Z > ~X

3. X > (Y v ~X)       1, addition
4. Y > Z              3,2 hypothetical syllogism
5. X > Z              1,4 hypothetical syllogism
6. ~Z > ~X            5, transposition

Edwin</pre>