a) $$\left(\frac{1}{4}\right)^2 = \frac{1^2}{4^2} = \frac{1}{16}$$
б) $$\left(\frac{3}{5}\right)^3 = \frac{3^3}{5^3} = \frac{27}{125}$$
в) $$\left(\frac{9}{11}\right)^2 = \frac{9^2}{11^2} = \frac{81}{121}$$
г) $$\left(\frac{5}{6}\right)^3 = \frac{5^3}{6^3} = \frac{125}{216}$$