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Math Help - logarithm equation

  1. #1
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    logarithm equation

    can someone please write back to me as soon as possible with the answer and working to this question, its got me totaly baffled!!


    2log21/x + 3log2x = 4
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  2. #2
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    Hello,

    Quote Originally Posted by jammy14 View Post
    can someone please write back to me as soon as possible with the answer and working to this question, its got me totaly baffled!!


    2log21/x + 3log2x = 4
    \log \frac 1x=-\log x

    Therefore, the equation becomes :

    -2\log_2 x+3 \log_2 x=4

    \log_2 x=4

    ---> \underbrace{2^{\log_2 x}}_{x}=2^4

    \boxed{x=16}
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  3. #3
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    thankx but could you please explain how you did the last bit-



    --->



    im not so good at this!!
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  4. #4
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    Quote Originally Posted by jammy14 View Post
    thankx but could you please explain how you did the last bit-



    --->



    im not so good at this!!
    Ok

    Basically, \log_a x=b means that x=a^b

    Or you can remember that a^{\log_a x}=x

    These are basic rules


    ------------

    For the latter part, 2^4=16
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  5. #5
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    Thumbs up

    thankx
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