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Math Help - Radical equation help

  1. #1
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    Radical equation help

    I'm having a hell of a time trying to answer this one question.
    sqrt(3m+7)-5=3m

    I got up to
    0=3(3m^2-m+6) but can't figure out how to factor any further and find the solution set. Any help would be appreciated. Thanks!
    Last edited by skunkape; April 29th 2010 at 07:35 AM. Reason: wrote the problem incorrectly
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  2. #2
    MHF Contributor
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    Hi

    The first thing to do to solve \sqrt{3m+7} -5 = 3m
    is to find the set of possible values for m

    3m+7 \geq 0

    m \geq -\frac{7}{3}

    Then \sqrt{3m+7} = 3m + 5

    Square both sides 3m+7 = (3m + 5)^2

    Expand the right member and rearrange to get a quadratic
    Solve and find the solutions that are greater than -7/3
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  3. #3
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    Thanks a bunch!
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  4. #4
    MHF Contributor
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    Sorry I forgot to tell you to check whether each of the two solutions of the quadratic satisfy the first equation
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