Question 1090514
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 1. ~M•(Z > R) 
 2. (~M v G) > ~U
 3. (~M v ~X) > ~B 
 4. (~B • ~U ) > (E > M)     / ~E

 5. ~M          1, simplification
 6. ~M v G      5, addition
 7. ~U          2,6, modus ponens
 8. ~M v ~X     5, addition
 9. ~B          3,8, modus ponens
10. ~B • ~U     9,7, conjunction
11. E > M       4,10, modus ponens
12. ~E          11,5, modus tollens

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