document.write( "Question 1188618:
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Algebra.Com's Answer #820130 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "1.	A ⊃ B\r\n" );
document.write( "2.	C ⊃ D\r\n" );
document.write( "3.	~(D ∨ B) // C ≡ A\r\n" );
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document.write( "4.      ~D • ~B            3, DeMorgan's law\r\n" );
document.write( "5.      ~D                 4, simpification\r\n" );
document.write( "6.      ~C                 2,5, modus tollens\r\n" );
document.write( "7.      ~C ∨ A             6, addition\r\n" );
document.write( "8.       C ⊃ A             7, material implication\r\n" );
document.write( "9.      ~B • ~D            4, commutation\r\n" );
document.write( "10.     ~B                 9, simplification\r\n" );
document.write( "11.     ~A                 1,10, modus tollens\r\n" );
document.write( "12.     ~A ∨ C             11, addition\r\n" );
document.write( "13.      A ⊃ C             12, material implication\r\n" );
document.write( "14,      C ≡ A             8,13, material equivalence \r\n" );
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document.write( "Edwin
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