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Solve for x

2(27)^x = 9^(x-1)
 Mar 28, 2012
 #1
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2*(27^x) = 9^(x-1)
ln on both sides:
ln( 2*(27^x) ) = ln( 9^(x-1) )
x * ln( 27 ) + ln( 2 ) = (x-1) * ln( 9 )
x * ln( 27 ) + ln( 2 ) = x * ln( 9 ) - ln( 9 )
x * ln( 27 ) = x * ln( 9 ) - ln( 9 )-ln( 2 )
x * ln( 27 ) = x * ln( 9 ) - ln( 9 )-ln( 2 )
x * ln( 27 ) -x * ln( 9 ) = - ln( 9 )-ln( 2 )
x * ( ln( 27 ) - ln( 9 ) ) = - ln( 9 )-ln( 2 )
x = (- ln( 9 )-ln( 2 )) / ( ln( 27 ) - ln( 9 ) )
[input](- ln( 9 )-ln( 2 )) / ( ln( 27 ) - ln( 9 ) )[/input]
 Mar 28, 2012

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