document.write( "Question 1009889: 1. (P v F) -> (A v D)
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Algebra.Com's Answer #625381 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Indirect proof\r\n" );
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document.write( " 1. (P v F) -> (A v D)\r\n" );
document.write( " 2. A -> (M ^ ~P)\r\n" );
document.write( " 3. D -> (C ^ ~P)      / ~P\r\n" );
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document.write( " 4. ~~P                        AIP\r\n" );
document.write( " 5. P                        4, DN \r\n" );
document.write( " 6. P v F                    5, add.\r\n" );
document.write( " 7. A v D                  1,6, MP\r\n" );
document.write( " 8. (M ^ ~P) v (C ^ ~P)  7,2,3, DE (disjunctive elimination)\r\n" );
document.write( " 9. (M v C) ^ ~P             8, distribution\r\n" );
document.write( "10. ~P ^ (M v C)             9, commutation\r\n" );
document.write( "11. ~P                      10, simp.\r\n" );
document.write( "12. P^~P                  5,11, conj.\r\n" );
document.write( "13. ~P                    4-12  IP\r\n" );
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document.write( "Edwin
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