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Math Help - 2 more that seem overly simple to me

  1. #1
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    2 more that seem overly simple to me

    Find Y

    -2x -y = 2
    5x+2y=-3



    Write an equation in std form

    (-3,5) (5,3)



    Thanks as always
    For some reason I struggle on things that should be easy.
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  2. #2
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    Quote Originally Posted by ColoMath View Post
    Find Y
    -2x -y = 2
    5x+2y=-3

    Write an equation in std form
    (-3,5) (5,3)...
    Hi,

    multiply the 1rst equation by 2 and then add:

    -4x - 2y = 4
    5x + 2y = -3
    --------------
    x = 1 Substitute this value into the 1rst equation:

    -2*1 - y = 2
    -y = 4
    y = -4

    I assume that you are looking for the equation of a straight line passing through these two points:

    (y - 5)/(x- (-3)) = (3 - 5)/(5 - (-3)) = (-2)/(8) = -1/4 that is the slope of the line:

    y - 5 = -1/4*(x+3)
    y - 5 = -1/4*x - 3/4

    y = -1/4*x + 17/4
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  3. #3
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    Quote Originally Posted by earboth View Post
    Hi,

    multiply the 1rst equation by 2 and then add:

    -4x - 2y = 4
    5x + 2y = -3
    --------------
    x = 1 Substitute this value into the 1rst equation:

    -2*1 - y = 2
    -y = 4
    y = -4

    I assume that you are looking for the equation of a straight line passing through these two points:

    (y - 5)/(x- (-3)) = (3 - 5)/(5 - (-3)) = (-2)/(8) = -1/4 that is the slope of the line:

    y - 5 = -1/4*(x+3)
    y - 5 = -1/4*x - 3/4

    y = -1/4*x + 17/4
    Awesome, thank you
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  4. #4
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    Quote Originally Posted by earboth View Post

    I assume that you are looking for the equation of a straight line passing through these two points:

    (y - 5)/(x- (-3)) = (3 - 5)/(5 - (-3)) = (-2)/(8) = -1/4 that is the slope of the line:

    y - 5 = -1/4*(x+3)
    y - 5 = -1/4*x - 3/4

    y = -1/4*x + 17/4
    Is that Standard form? I think that's the slope intercept form.
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  5. #5
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by ColoMath View Post
    Is that Standard form? I think that's the slope intercept form.
    the equation of a line in standard form is ax + by = c, where a, b and c are real numbers. it looks better if they are integers.

    so we have y = -1/4*x + 17/4

    move x to one side and multiply through by 4, we get:

    x + 4y = 17
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