Question 387044: Solve for x: 16^x-5(8^x)=0
Thanks :)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Solve for x: 16^x-5(8^x)=0
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Convert to base 2:
2^(4x) = 5*2^(3x)
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Divide both sides by 2^(3x) to get:
2^x = 5
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Take the log:
x(log(2)) = log(5)
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x = [log(5)]/[log(2)]
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x = 2.3219
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OR
2^(4x) - 5*2^(3x) =
Factor:
2^(3x)[2^x-5] = 0
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2^(3x) = 0 or 2^x = 5
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No power or 2 gives 0 so 2^(3x)=0 has no solution.
But 2^x = 5 has x = 2.3219 as a solution.
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Cheers,
Stan H.
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