SOLUTION: lnx+ln(x+1)=2 I must solve for x, I keep coming across problems like this and also 3logx-log2x=2 and never really remember how to solve them.

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: lnx+ln(x+1)=2 I must solve for x, I keep coming across problems like this and also 3logx-log2x=2 and never really remember how to solve them.      Log On


   



Question 603512: lnx+ln(x+1)=2 I must solve for x, I keep coming across problems like this and also 3logx-log2x=2 and never really remember how to solve them.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
lnx+ln(x+1)=2 I must solve for x, I keep coming across problems like this and also 3logx-log2x=2 and never really remember how to solve them.
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ln(x) + ln(x+1) = 2
---
ln(x(x+1)) = 2
x^2+x = e^2
x^2+x-e^2 = 0
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Use the Quadratic Formula to solve.
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3logx-log2x=2
log(x^3)-[log2x] = 2
------
log[x^3/(2x)] = 2
log[x^2/2] = 2
---
x^2/2 = 100
x^2 = 200
x = 10*sqrt(2)
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Cheers,
Stan H.
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