SOLUTION: Solve for x, to three significant digits: 2^4x + 2^2x = 132.

Question 1058666: Solve for x, to three significant digits: 2^4x + 2^2x = 132.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Solve for x, to three significant digits: 2^4x + 2^2x = 132.
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2^(4x) + 2^(2x) = 132
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4^(2x) + 4^x - 132 = 0
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(4^x)^2 + 4^x - 132 = 0
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Factor::
Let w = 4^x
w^2 + w - 132 = 0
(w-11)(w+12) = 0
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w = 11 or w = -12
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Solve for "x":
4^x = 11
x = log(11)/log(4) = 1.730
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OR
4^x = -12
Comment:: No power of 4 can be negative.
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Only solution:: x = 1.730
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Cheers,
Stan H.
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