document.write( "Question 1195750: phil 10\r
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Algebra.Com's Answer #828302 by mccravyedwin(406)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "1. Z v ~Z                  tautology\r\n" );
document.write( "2. Z v (~Z v Q)            1, addition\r\n" );
document.write( "3. Z v (Z ⊃ Q)             2, material implication\r\n" );
document.write( "4. [Z v (Z ⊃ Q)] v M       3, addition\r\n" );
document.write( "5.  ~~{[Z v (Z ⊃ Q)] v M}  4, double negation\r\n" );
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document.write( "But that does not use indirect proof\r\n" );
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document.write( "1.                         | ~~~{[Z v (Z ⊃ Q)] v M}I    AIP\r\n" );
document.write( "2.                         |\r\n" );
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document.write( "Edwin
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