Answer
$-1/32-\sqrt 3/32*i$
Work Step by Step
The expression inside of the parenthesis can be recognized from the unit circle as theta $=\pi/6$. and the magnitude is $\sqrt {3+1}=2$.
Thus we apply De Moivre's Theorem,
$(2cis(\pi/6))^{-4}=2^{-4}*cis((-2pi/3)$
That simplifies to,
$1/16*(-1/2-\sqrt 3*i/2)$
