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Math Help - Please solve logarithmic equation

  1. #1
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    Please solve logarithmic equation

    Please help solve equation:
    ln x + ln (x + 2) = 4
    ln x (x + 2) = 4
    e ^ 4 = x (x + 2)

    What do I do next to solve for x?

    Thank you.
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  2. #2
    MHF Contributor red_dog's Avatar
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    First of all we have to put the conditions for the existence of the logarithms:
    x>0, \ x+2>0\Rightarrow x\in(0,\infty).
    Now solve the quadratic x^2+2x-e^4=0 and choose the right solution which is x=-1+\sqrt{1+e^4}
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  3. #3
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    Thank you
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