Question 11 Mark
$\log \left(\frac{1}{81}\right)$ to the base 9 is equal to _________________
Answer
View full question & answer→-2 , because
$
\begin{aligned}
\log _9\left(\frac{1}{81}\right) & =\log _9\left(\frac{1}{9^2}\right)=\log _9(9)^{-2} \\
& =-2 \log _9 9=-2 \times 1=-2
\end{aligned}
$
[Applying rules $\log _a(m)^n=n \log _a m$ and $\left.\log _a a=1\right]$
$
\begin{aligned}
\log _9\left(\frac{1}{81}\right) & =\log _9\left(\frac{1}{9^2}\right)=\log _9(9)^{-2} \\
& =-2 \log _9 9=-2 \times 1=-2
\end{aligned}
$
[Applying rules $\log _a(m)^n=n \log _a m$ and $\left.\log _a a=1\right]$
