Answer
$x \approx 7.055$
Work Step by Step
$81000 (\frac{1}{9})^{x} = 0.015$
$(\frac{1}{9})^{x} = \frac{0.015}{81000}$
$x = \log_{\frac{1}{9}} (\frac{0.015}{81000})$
$x = \frac{\log \frac{0.015}{81000}}{\log \frac{1}{9}}$
by GDC / calculator
$x = 7.055223...$
$x \approx 7.055$