document.write( "Question 188809: I cannot solve this: I can use: Transportation, Material Implication, Material Equivalence, Exportation, Tautology, Double Negation, Commutation, Association, Distribution, Demorgan's Theorem, Modus Ponems, Modus Tollens, Hypothetical Syllogism, Conjunstion, Simplification, Addition, Constructive Dilemma, Absorption and Disjuntive Syllogism. \r
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Algebra.Com's Answer #141608 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "1.  p -> (q -> r)\r\n" );
document.write( "2.  ~ (q & ~r) -> s\r\n" );
document.write( "3.  s -> t\r\n" );
document.write( "4.  t <--> (q & ~s) Therefore: p <--> s\r\n" );
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document.write( "5.  ( ~q v ~~r) -> s                            2     DeMorgan's Theorem\r\n" );
document.write( "6.  ( ~q v r) -> s                              5     Double Negation \r\n" );
document.write( "7.  (q -> r ) -> s                              6     Material Implication\r\n" );
document.write( "8.  p -> s                                      1,7   Hypothetical Syllogism     \r\n" );
document.write( "9.  [t -> (q & ~s)] & [(q & ~s) -> t]           4     Material Equivalence\r\n" );
document.write( "10.  t -> (q & ~s)                              9     Simplification\r\n" );
document.write( "11. ~t v (q & ~s)                               10    Material Implication\r\n" );
document.write( "12. (~t v q) & (~t v ~s)                        11    Distribution\r\n" );
document.write( "13. (~t v ~s) & (~t v q)                        12    Commutation\r\n" );
document.write( "14. ~t v ~s                                     13    Simplification\r\n" );
document.write( "15. t -> ~s                                     14    Material Implication\r\n" );
document.write( "16. s -> ~s                                     3,15  Hypothetical Syllogism \r\n" );
document.write( "17. ~s v ~s                                     16    Material Implication\r\n" );
document.write( "18. ~s                                          17    Tautology\r\n" );
document.write( "19. ~s v p                                      18    Addition\r\n" );
document.write( "20. s -> p                                      19    Material Implication\r\n" );
document.write( "21. (p -> s) & (s -> p)                         8,20  Conjunction\r\n" );
document.write( "22. p <--> s                                    21    Material Equivalence\r\n" );
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