SOLUTION: please help me solve this equation {{{ e^x-12e^(-x)-1=0}}} thanks

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Question 478370: please help me solve this equation +e%5Ex-12e%5E%28-x%29-1=0 thanks
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
e^x-12e^(-x)-1=0
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e^x -12/e^x -1 = 0
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Multiply thru by e^x to get:
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e^(2x) - 12 - e^x = 0
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This is a quadratic in e^x:
Let e^x = w
Substitute to get:
w^2 -w - 12 = 0
Factor:
(w-4)(w+3) = 0
Positive solution:
w = 4
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So, e^x = 4
x = ln(4)
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Cheers,
Stan H.