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Can you show me how to solve this logarithmic equation? log(x-9)=1-logx?

Update:

thanks Helmet, that gave me the number i was looking for.

3 Answers

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  • Helmut
    Lv 7
    1 decade ago
    Favorite Answer

    Hopefully log means log to the base10.

    If so, 1 = log(10)

    log(x-9) = log(10) - log(x)

    log(x-9) = log(10/x)

    x - 9 = 10/x

    x^2 - 9x - 10 = 0

    (x - 10)(x + 1) = 0

    x = - 1, 10

    Reject - 1 since you cannot take the log of a negative number.

  • ?
    Lv 4
    4 years ago

    logx+log(x+one million)=log56 logx(x+one million) = log56 x(x+one million) = fifty six x^2+x = fifty six x^2+x-fifty six =0 (x+8)(x-7) = 0 x=-8 or x=7 subsequently x=7 is the only answer and ignore with regards to the answer x=-8 is as a results of the fact the logarithm of a destructive extensive type isn't plausible.

  • 1 decade ago

    Since you have log on both sides of the equation and they both have the same base you can get rid of them. And then you are left with: x-9=x. So basically you just solve that for x.

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