Question

Log81 1/9= need help with this

Answer 1

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. 

Answer 2

$log_{81}(\frac{1}9})$
$81^{x} = \frac{1}{9}$
$ln(81^{x}) = ln(\frac{1}{9})$
$x\ln(81) = ln(\frac{1}{9})$
$\frac{x\ln(81)}{ln(81)} = \frac{ln(\frac{1}{9})}{ln(81)}$
$x = \frac{ln(\frac{1}{3})^{2}}{ln(3)^{4}}$
$x = \frac{2ln(\frac{1}{3})}{4ln(3)}$
$x = \frac{ln(\frac{1}{3})}{2ln(3)}$
$x = \frac{-ln(3)}{2ln(3)}$
$x = -\frac{1}{2}$