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Math Help - log question

  1. #1
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    log question

    Don't really know where to start on this one.

    Find all real solutions.

    log_{2}(x-2) + log_{2}(x+1) = log_{2}10
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  2. #2
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    Quote Originally Posted by smplease View Post
    Don't really know where to start on this one.

    Find all real solutions.

    log_{2}(x-2) + log_{2}(x+1) = log_{2}10
    Here's a start:

    Use  log_a (x) + log_a (y) = log_a (xy)

    You can then remove the logs and solve for x.
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  3. #3
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    Quote Originally Posted by smplease View Post
    Don't really know where to start on this one.

    Find all real solutions.

    log_{2}(x-2) + log_{2}(x+1) = log_{2}10

     \log_{2}(x-2) (x+1) = \log_{2}10

     (x-2) (x+1) = 10
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  4. #4
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    I got

    x^2 - x -12 = 0

    (x+3)(x-4) = 0

    x = -3, or
    x = 4

    Have I gone to far?

    Thanks for your help guys
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  5. #5
    MHF Contributor harish21's Avatar
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    Quote Originally Posted by smplease View Post
    I got

    x^2 - x -12 = 0

    (x+3)(x-4) = 0

    x = -3, or
    x = 4

    Have I gone to far?

    Thanks for your help guys
    Thats exactly what you need!
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