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Math Help - Algebraically find the coordinates.

  1. #1
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    Algebraically find the coordinates.

    Find algebraically the coordinates of the points of intersection of the graph with this equation:

    y=3x-1<br />
y=3+3/(x-1)

    this is what i did (but turned out wrong?

    3x-1=3+3/(x-1)

    multiplied everything by x-1
    (x-1)(3x-1)= 3x-3 +2

    (X-1)(3X-1)=3x-1

    x-1=0

    x=1

    but that doesn't work, and either way the answer is meant to be:

    (2,5) (1/3,0)

    No clue what to do.
    Thanks.
    Last edited by juliak; October 1st 2008 at 03:05 AM.
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  2. #2
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    Quote Originally Posted by juliak View Post
    F
    y=3x-1<br />
y=3+3/(x-1)



    multiplied everything by x-1
    (x-1)(3x-1)= 3x-3 +2

    (X-1)(3X-1)=2x-1
    3x - 3 + 2 = 3x - 1 not 2x -1

    Bobak
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  3. #3
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    oooops.
    typo.

    edited.
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  4. #4
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    Quote Originally Posted by juliak View Post
    (x-1)(3x-1)= 3x-3 +2

    (X-1)(3X-1)=3x-1

    x-1=0 this is wrong

    x=1

    Two things here, firstly if you do cancel a factor of 3x-1 from both side the right hand side becomes 1 not zero, also by doing that your losing a solution to the equation. your working should look something like this...

    (x-1)(3x-1)=3x-1
    (x-1)(3x-1) - (3x-1)=0
    (3x-1)((x-1) -1)=0
    (3x-1)(x-2)=0

    Bobak
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  5. #5
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    oooo
    thanks!
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