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Math Help - Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

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    Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

    Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

    Does anyone know how to find g?

    I tried the following:

    sqrt(x) results in x + 3 which is wrong...
    sqrt(x) + 2 results in x + 4sqrt(x) + 7 which is wrong...
    etc...

    Nothing seems to work.... How do I do this? Please help!
    Last edited by Lotte1990; March 10th 2012 at 12:48 PM.
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  2. #2
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    Re: Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

    Nevermind, sqrt(x + 2) is the right answer. I finally found it!
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    Re: Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

    Quote Originally Posted by Lotte1990 View Post
    Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

    Does anyone know how to find g?
    Can you solve {y^2} + 3 = 5 + x for y~?
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  4. #4
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    Re: Find g for f(g(x)) = 5 + x when f(x) = x^2 + 3

    Quote Originally Posted by Lotte1990 View Post
    Nevermind, sqrt(x + 2) is the right answer. I finally found it!
    Looks like g can be the negative of this as well.
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