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Math Help - simultaneous equations urgant for homework

  1. #1
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    Smile simultaneous equations urgant for homework

    simultaneous equations

    x + 2y = 4
    3x - 4y = 7
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  2. #2
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    Quote Originally Posted by vtaylor View Post
    simultaneous equations

    x + 2y = 4
    3x - 4y = 7
    Hello,

    there are a lot of different ways to solve such a system of equations. Here is one:

    A: x + 2y = 4 ===> x = 4 - 2y
    B: 3x - 4y = 7 Now plug in the term for x from equation A:

    3(4 - 2y) - 4y = 7
    12 - 6y -4y = 7

    -10y = - 5
    y = Plug in this value into equation A:

    x = 4 - 2* = 3
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  3. #3
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    Hello, vtaylor!

    Another method . . . "Elimination"



    . . .x + 2y .= .4 .[1]
    . . 3x - 4y .= .7 .[2]

    Multiply [1] by 2: . 2x + 4y .= .8
    . . . . . . Add [2]: . 3x .- 4y .= .7

    And we have: . 5x = 15 . . x = 3

    Substitute into [1]: .3 + 2y .= .4 . . y =

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  4. #4
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    Quote Originally Posted by vtaylor View Post
    simultaneous equations

    x + 2y = 4
    3x - 4y = 7
    Hello,

    next method:

    x + 2y = 4 ===> y = -x + 2
    3x - 4y = 7 ===> y = 3/4x - 7/4

    These terms of y must be equal:

    -x + 2 = 3/4x - 7/4
    -5/4x = -15/4
    x = 3 Plugin this value into the first equation:
    y = -*3 + 2 =
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  5. #5
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    good review this is on my final next week
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