document.write( "Question 1142561: P · (Q ∨ R), Q ⊃ S, R ⊃ T ∴ ~T ⊃ S \n" ); document.write( "
Algebra.Com's Answer #763248 by Edwin McCravy(20054)\"\" \"About 
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document.write( " 1.   P · (Q ∨ R)\r\n" );
document.write( " 2,   Q ⊃ S\r\n" );
document.write( " 3.   R ⊃ T        ∴ ~T ⊃ S\r\n" );
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document.write( "               | 4.  ~T               Assumption for Indirect Proof\r\n" );
document.write( "               | 5.  ~R               3,4, Modus Tollens\r\n" );
document.write( "               | 6.  (Q ∨ R) · P      1, Commutation\r\n" );
document.write( "               | 7.  Q ∨ R            6, Simplification\r\n" );
document.write( "               | 8.  R ∨ Q            7, Commutation\r\n" );
document.write( "               | 9.  Q                8,5, Disjunctive Syllogism  \r\n" );
document.write( "               |10.  S                \r\n" );
document.write( "11. ~T ⊃ S               lines 4-10 Indirect Proof\r\n" );
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document.write( "Edwin
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