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Math Help - Systems of Liner Equations

  1. #1
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    Systems of Liner Equations

    I know how to solve systems of linear equations using 2 equations. I can even solve a system of linear equations with 3 quations using Gaussian Elimination. But, for some reason, I cannot solve this one. I've plugged it into wolframalpha's engine to see what the correct answers are, but it does not show the steps. Any help would be greatly appreciated.

    2/x + 3/y = -2
    4/x - 5/y = 1
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  2. #2
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    Quote Originally Posted by franzpulk View Post
    I know how to solve systems of linear equations using 2 equations. I can even solve a system of linear equations with 3 quations using Gaussian Elimination. But, for some reason, I cannot solve this one. I've plugged it into wolframalpha's engine to see what the correct answers are, but it does not show the steps. Any help would be greatly appreciated.

    2/x + 3/y = -2
    4/x - 5/y = 1
    multiply every term in the first equation by -2 and combine to eliminate the x terms ...

    -4/x - 6/y = 4

    4/x - 5/y = 1
    ---------------

    -11/y = 5

    y = -11/5

    sub the value for y into either original equation and solve for x ...

    2/x - 15/11 = -2

    2/x = -7/11

    x = -22/7
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  3. #3
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    I got it now. I was multiplying both through by xy to begin with instead of eliminating one and then multiplying through by xy.

    Thanks.
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