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Math Help - Solving equations with roots

  1. #1
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    Solving equations with roots

    Ok, how would I go about solving the following equation with algebra?

    a + a^(1/2) = 20

    OR: a plus the square root of a equals 20.

    I can't seem to work out how you do it. I know that the answer in this case is a = 16, but I'm not sure how you would arrive there with algebra. Any help would be appreciated.
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  2. #2
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    Hello,
    Quote Originally Posted by Wowsa View Post
    Ok, how would I go about solving the following equation with algebra?

    a + a^(1/2) = 20

    OR: a plus the square root of a equals 20.

    I can't seem to work out how you do it. I know that the answer in this case is a = 16, but I'm not sure how you would arrive there with algebra. Any help would be appreciated.
    substitute b=a^{1/2}
    note that a=(a^{1/2})^2=b^2

    so you're in front of a quadratic get the values for b and keep the positive ones
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  3. #3
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    Quote Originally Posted by Moo View Post

    so you're in front of a quadratic get the values for b and keep the positive ones
    Could you explain that bit to me in more detail please? I'm a bit of a newb at algebra and I'm not sure I understand what you did.
    Last edited by Wowsa; October 5th 2008 at 03:47 AM.
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  4. #4
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    I've worked out what you meant now, thanks for your help.
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