document.write( "Question 1090916: Proof for:\r
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Algebra.Com's Answer #705359 by Edwin McCravy(20055)\"\" \"About 
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document.write( "1. U v (~U > ~B) \r\n" );
document.write( "2. ~B > (R > U)\r\n" );
document.write( "3. ~U           / ~R\r\n" );
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document.write( "4. ~U > ~B          1,3, Disjunctive Syllogism\r\n" );
document.write( "5. ~B               4,3, Modus Ponens\r\n" );
document.write( "6. R > U            2,5, Modus Ponens\r\n" );
document.write( "7. ~R               6,3, Modus Tollens\r\n" );
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document.write( "Edwin

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