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anonymous

  • 2 years ago

lol

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  1. anonymous
    • 2 years ago
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    add both equations

  2. anonymous
    • 2 years ago
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    you'll get 2x = 22

  3. anonymous
    • 2 years ago
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    solve for that, and you'll get 11

  4. anonymous
    • 2 years ago
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    I though that too, but that's not an answer. :(

  5. anonymous
    • 2 years ago
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    thought*

  6. anonymous
    • 2 years ago
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    what are the options?

  7. anonymous
    • 2 years ago
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    -22 -12 -2

  8. anonymous
    • 2 years ago
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    I have to go, I'll respond to this in a little bit. Sorry.

  9. tkhunny
    • 2 years ago
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    x + y = 12 x - y = 10 D = (1)(-1)-(1)(1) Dx = (12)(-1)-(10)(1) Dy = (1)(10)-(1)(12)

  10. anonymous
    • 2 years ago
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    That's fine. Thanks though :)

  11. anonymous
    • 2 years ago
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    Are you saying it's -22? It's asking for the x determinant if you're wondering. I just want to be able to solve the future ones. :)

  12. mathmale
    • 2 years ago
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    @ambeeeerlw : Determinants are not used much any longer. However, you're apparently expected to know how to apply determinants to solving systems of linear equations. Have you tried looking up "determinants" on the 'Net? If you want to learn how do use determinants, either @tkhunny or I would be happy to help you ... but we do not give out just answers.

  13. anonymous
    • 2 years ago
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    I actually wasn't expecting just answers, I was double checking his work so I'd know how to future problems. I'm not trying to just collect answers, I swear. I have looked it up, but I can;t a way that explains it well enough where I fully understand. :( Can you help me?

  14. anonymous
    • 2 years ago
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    ( or her work, I didn't see who it was)

  15. tkhunny
    • 2 years ago
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    "Cramer's Rule" is very interesting. It just works. It leans toward what we like to call an "Existence" result. This means it may or may not be very useful in the real world, but it demonstrates that (or under what conditions) the solution exists. Good thing to know.

  16. anonymous
    • 2 years ago
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    My teacher didn't even mention it is "Cramer's Rule," so that's a nice factor to know.. I do online school, and I can't really get it touch with my teacher, reasoning behind me getting help from her.

  17. mathmale
    • 2 years ago
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    @tkhunny typed this out for you earlier: x + y = 12 x - y = 10 D = (1)(-1)-(1)(1) Dx = (12)(-1)-(10)(1) Dy = (1)(10)-(1)(12) First, he found the "system determinant." He realized that x + y = 12 x - y = 10 can be re-written as 1x+1y=12 1x-1y=10 which we need to do because we need those coefficients of x and y. Notice how the coefficients (alone) are 1 1 1 -1 tkhunny now finds the "system determinant."|dw:1396529907980:dw|

  18. mathmale
    • 2 years ago
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    The result is -1 -1, or -2. The system determinant is -2. Note that this is exactly the result obtained by tkhunny earlier. Have you seen this kind of work done before?

  19. anonymous
    • 2 years ago
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    Yes, that is the only one have and that I understand.

  20. mathmale
    • 2 years ago
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    Good. Now we need to find x. We take the system determinant, toss out the first column, and replace it with the constants (12 and 10):|dw:1396530274277:dw|

  21. anonymous
    • 2 years ago
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    the products of those would be -12 and -10, right?

  22. mathmale
    • 2 years ago
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    Right, and that adds up to -22. Thus, your x is found in this manner:|dw:1396530623039:dw|

  23. anonymous
    • 2 years ago
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    10?

  24. mathmale
    • 2 years ago
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    close. Try again.

  25. mathmale
    • 2 years ago
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    and your y value is

  26. anonymous
    • 2 years ago
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    I meant 11, oops :p

  27. anonymous
    • 2 years ago
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    y value is 1? I think

  28. mathmale
    • 2 years ago
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    |dw:1396530712310:dw|

  29. mathmale
    • 2 years ago
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    Cool. Yes, y=1. Solution is (11,1). congrats!

  30. anonymous
    • 2 years ago
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    I don't understand because the answers are only -22,-12, and -2. This is what confuses me

  31. anonymous
    • 2 years ago
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    Is it asking for another part of the question? I'm unsure.

  32. mathmale
    • 2 years ago
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    @tkhunny's "answers" are intermediate results. He gave you D=-2, Dx = -22 and Dy = -2.|dw:1396531164233:dw|

  33. mathmale
    • 2 years ago
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    that's right!! they are both modifications of the system determinant.

  34. mathmale
    • 2 years ago
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    And nothing to apologize for! I so much appreciate your sticking with this until completion. Hope to get to work with you again.

  35. mathmale
    • 2 years ago
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    That's like music to the ears! :)

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