SOLUTION: I need to solve the following equation rounded to 3 decimal places: I need to see how it's done, so i can practice ln x + ln (x+7) = -5 Thank you.

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: I need to solve the following equation rounded to 3 decimal places: I need to see how it's done, so i can practice ln x + ln (x+7) = -5 Thank you.      Log On


   

Question 366154: I need to solve the following equation rounded to 3 decimal places:
I need to see how it's done, so i can practice
ln x + ln (x+7) = -5
Thank you.
Found 2 solutions by Fombitz, stanbon:
Answer by Fombitz(32388) About Me  (Show Source):
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
ln x + ln (x+7) = -5
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Since ln(A) + ln(B) = ln(AB)
you get:
ln[x(x+7)] = -5
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That means "the exponent of "e" that gives you
x^2+7x is -5"
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Solve x^2+7x = e^-5
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x^2 + 7x = 0.0067
x^2 + 7x - 0.0067 = 0
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Positive solution:
I graphed the equation and found zeroes at
x = 9.57x10^-4
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Cheers,
Stan H.
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