SOLUTION: Solve the equation: e^x - 12e^-x - 1 = 0

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Question 821874: Solve the equation:
e^x - 12e^-x - 1 = 0
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

Solve the equation:

e^x - 12e^-x - 1 = 0

e%5Ex+-+12%2Fe%5Ex+-+1+=+0   |Multiplying thru by e^x so as all denominators = 1

  e^(2x) - 12 - e^x = 0

 +e%5E%282x%29++-+e%5Ex++-12+=+0

 (e^x - 4)(e^x + 3) = 0   (tossing out negative value for e^x

    e^x = 4

       x = ln(4)