SOLUTION: Please help me solve the exponential and logarithmic equation: (4^x)-3(4^-x)=8

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Question 993221: Please help me solve the exponential and logarithmic equation:
(4^x)-3(4^-x)=8

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
solve the exponential and logarithmic equation:
(4^x)-3(4^-x)=8
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4^x - 3(1/4^x) = 8
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Multiply thru by 4^x to get::
(4^x)^2 - 3 = 8(4^x)
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(4^x)^2 - 8(4^x) - 3 = 0
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Let 4^x = w
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w^2 - 8w - 3 = 0
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w = [8+-sqrt(64-4(-3)]/2
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w = [8+-sqrt(76)]/2
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Find the positive value of w::
w = 8.36
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Solve for "x"::
4^x = 8.36
x = log(8.36)/log(4) = 1.53
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Cheers,
Stan H.
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