<PRE><B>Question 468208</B>
ln(x+9)-ln(x-5)=ln(x+7)-ln(x-4). 
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ln[(x+9)/(x-5)] = ln[(x+7)/(x-4)]
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(x+9)/(x-5) = (x+7)/(x-4)
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Cross-multiply
x^2 + 5x - 36 = x^2 + 2x - 35
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3x = 1
x = 1/3
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Why is that not a solution?
If you substitute that into the original equation
you would get:
ln((1/3)+9) - ln((1/3)-5) = ln((1/3)+7 - ln((1/3)-4)]
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The ln((1/3)-5) and the ln((1/3)-4) are both undefined.
because there is not ln of a negative number.
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Therefore, no solution.
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cheers,
stan H.</PRE>