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Math Help - Trying to make (x) the subject?

  1. #1
    Senior Member
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    Trying to make (x) the subject?

    I have;

    3x - 2y = 1
    4x + y 3

    I think I get rid of the fraction and end up with;

    3x - 2y
    4x + y

    Then I think;

    3x - 2y = -4x + y

    Then;

    -2y + y = -4x + 3x
    - y = x

    therefore;

    x = -y

    Please advise if I got it right?

    Thanks

    David

    The above method didn't look right after posting?

    3x - 2y = - 4x - y
    4x + y = - 3x +2y
    4x - 3x = x
    y - 2y = -y

    therefore;

    x = - y

    I think?
    Last edited by David Green; July 21st 2011 at 02:36 PM.
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  2. #2
    Master Of Puppets
    pickslides's Avatar
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    Re: Trying to make (x) the subject?

    Quote Originally Posted by David Green View Post

    3x - 2y = 1
    4x + y 3
    \displaystyle \frac{3x-2y}{4x+y} = \frac{1}{3}

    Cross multiplying

    \displaystyle 3(3x-2y) = 1(4x+y)

    Expanding

    \displaystyle 9x-6y = 4x+y

    Grouping like terms

    \displaystyle 9x-4x = y+6y

    \displaystyle 5x = 7y

    \displaystyle x = \frac{7y}{5}
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