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← 07-12 SAT

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Showing Revision 1 created 10/03/2012 by Amara Bot.

  1. And the answer here is that you should set X1 to true,
  2. X2 to false, and X3 to false,
  3. and the way to figure this out is,
  4. at least for me, it was the following:
  5. So you have to set X1 to true
  6. because otherwise this thing here will be false,
  7. and you see we have a number of N's,
  8. so if this evaluates to zero, the whole formula cannot be satisfied.
  9. So we already know this assignment here,
  10. which gives us a 1 here and a 0 here also.
  11. Now since we have a 0 here,
  12. we must make sure that not X2 evaluates to true,
  13. so we have to set it to false,
  14. and if we set it to false, we get a 1 here, get a 1 here, and a 0 here.
  15. And since this here has been set to 0,
  16. and again we need to make sure that these brackets evaluate to true.
  17. We also have to set X3 to false
  18. so that this here becomes a 1,
  19. which gives us a 1 here as well and a 0 here as well.
  20. And so for the whole thing, this here evaluates to 1,
  21. this here evaluates to 1 because this evaluates to 1, and this one here as well.
  22. This goes to 1, and this goes to 1 here as well.
  23. And so we have 1 and 1 and 1 and 1,
  24. which satisfies the whole formula.