Answer
$\displaystyle \frac{1}{16}$
Work Step by Step
$8^{-4/3}=$ ... recognize $8=2^{3}$
$=(2^{3})^{-4/3}=$ ...use: $(a^{m})^{n}=a^{mn}$
$=2^{-4}=$ ...use: $\displaystyle \frac{1}{a^{n}}=a^{-n}$
$=\displaystyle \frac{1}{2^{4}}$
$= \displaystyle \frac{1}{16}$