document.write( "Question 1178624: Use Indirect proof to solve the following:\r
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Algebra.Com's Answer #808132 by Edwin McCravy(20055)\"\" \"About 
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document.write( "1.  B ≡ (A • D)\r\n" );
document.write( "2.  ~A ⊃ (~B ⊃ C)                  / A ∨ C\r\n" );
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document.write( "              |3.  ~(A ∨ C)      Assumption for Indirect Proof\r\n" );
document.write( "              |4.  ~A • ~C                           3, DeMorgan's Law\r\n" );
document.write( "              |5.  ~A                                4, simplification\r\n" );
document.write( "              |6.  ~B ⊃ C                            2,5, Modus Ponens\r\n" );
document.write( "              |7.  ~C ⊃ ~~B                          6, transposition\r\n" );
document.write( "              |8.  ~C ⊃ B                            7, double negation\r\n" );
document.write( "              |9.  ~C • ~A                           4, transposition\r\n" );
document.write( "              |10. ~C                                9, simplification\r\n" );
document.write( "              |11. B                                 8, Mudus Ponens   \r\n" );
document.write( "              |12. [B ⊃ (A • D)] • [(A • D) ⊃ B]    1, Material Equivalence\r\n" );
document.write( "              |13. B ⊃ (A • D)                      12, simplification\r\n" );
document.write( "              |14. A • D                             13,11\r\n" );
document.write( "              |15. A                                 14, simplification\r\n" );
document.write( "              |16. A • ~A                            15,5, conjunction   \r\n" );
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document.write( "17. A ∨ C      lines 3--16          Indirect Proof\r\n" );
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document.write( "Edwin
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