JAMB 2012 · UTME · Q7

If $\log_3 x^2 = -8$ , what is $x$ ?

Worked solution (try it first)

Change to index form: $x^2 = 3^{-8}$ .
Take the square root by halving the power: $x = 3^{-4}$ (taking the positive root).
$3^{-4} = \frac{1}{3^4} = \frac{1}{81}$ , option D.