Ответ:

Применяем свойства степеней:   [tex]\bf a^{-n}=\dfrac{1}{a^{n}}\ \ ,\ \ \ a^{n}\cdot a^{k}=a^{n+k}\ \ ,\ \ \dfrac{a^{n}}{a^{k}}=a^{n-k}[/tex]

[tex]1)\ \ \dfrac{1}{3^4}=3^{-4}\ \ ,\ \ \dfrac{1}{6}=6^{-1}\ \ ,\ \ \dfrac{1}{x^9}=x^{-9}\\\\\\2)\ \ 5^{-7}=\dfrac{1}{5^7}\ \ ,\ \ \dfrac{1}{7^{-1}}=7\ \ ,\ \ \dfrac{1}{a^{-11}}=a^{11}\ \ ,\ \ \dfrac{1}{(2y)^{-5}}=(2y)^5\\\\\\3)\ \ 4^{11}\cdot 4^{-9}=\dfrac{4^{11}}{4^9}=4^{11-9}=4^2=16\\\\6^{-5}:6^{-3}=\dfrac{1}{6^5}:\dfrac{1}{6^3}=\dfrac{6^3}{6^5}=\dfrac{1}{6^2}=\dfrac{1}{36}\\\\\\(2^{-2})^3=\Big(\dfrac{1}{2^2}\Bif)^3=\Big(\dfrac{1}{4}\Big)^3=\dfrac{1}{4^3}=\dfrac{1}{64}[/tex]