a) [tex](-2)^{-4}= \frac{1}{2^4} = \frac{1}{16} \in \ Q[/tex]
b)[tex]( \frac{\sqrt{5}}{\sqrt{11}} )^{-2}=( \frac{\sqrt{11}}{\sqrt{5}} )^{2}= \frac{11}{5} \in Q[/tex]
c)[tex]( \frac{2 \sqrt{3} }{3})^{-3} =( \frac{3 }{2 \sqrt{3}})^{3}= \frac{27}{ 24\sqrt{3} } = \frac{3 \sqrt{3} }{8} \notin Q[/tex]
d) [tex] \sqrt{6} ^{-2}= \frac{1}{ \sqrt{6} ^2} = \frac{1}{6} \in Q[/tex]
e)[tex](2 \sqrt{2} )^{-3}= \frac{1}{(2 \sqrt{2} )^{3}} = \frac{1}{16 \sqrt{2} } = \frac{ \sqrt{2}} {32} \notin Q[/tex]
