document.write( "Question 1209588: ((A & B) & C) & D, (D & C) → F, (B & C) → G, (A & D) → H ├ H & (G & F)\r
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Algebra.Com's Answer #849595 by Edwin McCravy(20055)\"\" \"About 
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document.write( " 1. ((A & B) & C) & D, \r\n" );
document.write( " 2. (D & C) → F, \r\n" );
document.write( " 3. (B & C) → G,\r\n" );
document.write( " 4. (A & D) → H        ├ H & (G & F)\r\n" );
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document.write( " 5. (A & B) & C            1, Simplification\r\n" );
document.write( " 6. A & B                  5, Simplification\r\n" );
document.write( " 7. A                      6, Simplification  \r\n" );
document.write( " 8. B & A                  6, Commutation\r\n" );
document.write( " 9. B                      8, Simplification  \r\n" );
document.write( "10. C & (A & B)            5, Commutation\r\n" );
document.write( "11. C                     10, Simplification\r\n" );
document.write( "12. D & ((A & B) & C)      1, Commutation\r\n" );
document.write( "13. D                     12, Simplification\r\n" );
document.write( "14. A & D               7,13, Conjunction\r\n" );
document.write( "15. H                      4, Modus Ponens\r\n" );
document.write( "16. B & C               9,11, Conjunction\r\n" );
document.write( "17. G                   3,16, Modus ponens\r\n" );
document.write( "18. D & C              13,11, Conjunction\r\n" );
document.write( "19. F                   2,15, Modus Ponens\r\n" );
document.write( "20. G & F              17,19, Conjunction\r\n" );
document.write( "21. H & (G & F)        15,20, Conjunction\r\n" );
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document.write( "        \r\n" );
document.write( "Edwin
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