SOLUTION: log base 10 (x+21) +log base 10 (x)= 2 the answer for x

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Question 426793: log base 10 (x+21) +log base 10 (x)= 2

the answer for x
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
log base 10 (x+21) +log base 10 (x)= 2
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log10[(x+2)(x)] = 2
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x(x+2) = 10^2
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x^2+2x-100 = 0
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x = [-2 +- sqrt(4-4*-100)]/2
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x = [-2 +- sqrt(404)]/2
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x = [-1 +- sqrt(101)]
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Positive solution:
x = -1+sqrt(101) = 9.0499
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Cheers,
Stan H.
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