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Log81 1/9= need help with this

User Constantin
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2 Answers

1 vote

log_(81)(\frac{1}9})

81^(x) = (1)/(9)

ln(81^(x)) = ln((1)/(9))

x\ln(81) = ln((1)/(9))

(x\ln(81))/(ln(81)) = (ln((1)/(9)))/(ln(81))

x = (ln((1)/(3))^(2))/(ln(3)^(4))

x = (2ln((1)/(3)))/(4ln(3))

x = (ln((1)/(3)))/(2ln(3))

x = (-ln(3))/(2ln(3))

x = -(1)/(2)
User Steinybot
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8.5k points
3 votes
If it is log 81 base 1/9=x, then you can make the following equation
(1/9)^x=81
x=-2
in this case since 9 squared is 81 and you need to flip the fraction so you add a negative,
Hope this helps.
User Eric Reboisson
by
7.4k points

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