document.write( "Question 1001436: Construct a direct proof of validity for the following argument.
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Algebra.Com's Answer #618620 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "The restriction only says not to use \"implication\".  \r\n" );
document.write( "It does NOT say not to use \"MATERIAL implication\".\r\n" );
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document.write( " 1.  B > (A > C)\r\n" );
document.write( " 2.  (B > C) > F      /A > F\r\n" );
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document.write( " 3. B > (~A v C)      1, Material implication\r\n" );
document.write( " 4. ~B v (~A v C)     3, Material implication\r\n" );
document.write( " 5. ~B v (C v ~A)     4, Commutation\r\n" );
document.write( " 6. (~B v C) v ~A     5, Association\r\n" );
document.write( " 7. (B > C) v ~A      6, Material implication\r\n" );
document.write( " 8. ~A v (B > C)      7, Commutation\r\n" );
document.write( " 9. A > (B > C)       8, Material implication\r\n" );
document.write( "10. A > F            9,2, Hypothetical syllogism\r\n" );
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document.write( "Edwin
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