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Math Help - Help Using Cramer's rule to solve system of equations

  1. #1
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    Joined
    Jun 2010
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    Help Using Cramer's rule to solve system of equations

    here's the matrix for it:



    | 2 0 -5 | | -1|
    |-2 1 3 | | 6|
    | 0 -1 6 | |-1|


    Underneath is what i have worked out for it, but the values didn't work when i plugged them into the equations. I'm not sure what I've done wrong. I went over it and couldn't find anything. Any help is appreciated!

    D=
    | 2 0 -5 |
    |-2 1 3 | = 2(1*6 – 3*-1) – 0(-2*6 – 3*0) + -5(-2*-1 – 1*0)
    | 0 -1 6 | = 18 – 0 – 15 = 3 D=3

    Dx1 =
    | -1 0 -5 |
    | 6 1 3 | = -1(1*6 – 3*-1) – 0(6*6 – 3*-1) + -5(6*-1 – 1*-1)
    |-1 -1 6 | = -9 – 0 + 25 = 16 Dx1 = 16

    Dx2 =
    | 2 -1 -5 |
    |-2 6 3 | = 2(6*6 – 3*-1) - -1(-2*6 – 3*0) + -5(-2*-1 – 6*0)
    | 0 -1 6 | = 78 – 12 – 10 = 56 Dx2 = 56

    Dx3 =
    | 2 0 -1|
    | -2 1 6 | = 2(1*-1 – 6*-1) – 0(-2*-1 – 6*0) + -1(-2*-1 – 1*0)
    | 0 -1 -1 | = 10 – 0 – 2 = 8 Dx3 = 8

    X1= Dx1/D
    = 16/3



    X2 = Dx2/D
    = 56/3


    X3 = Dx3/D
    = 8/3
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  2. #2
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    Joined
    Jun 2010
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    nevermind...found the problem.
    2x1 = 2, not 3 lol
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