[tex]\bf 2.\\ \\ \it =\Big[\Big(\dfrac{5}{8}\Big)^8\Big]^4:\Big(\dfrac{5}{8}\Big)^{30}=\Big(\dfrac{5}{8}\Big)^{32}:\Big(\dfrac{5}{8}\Big)^{30}=\Big(\dfrac{5}{8}\Big)^2=\dfrac{25}{49}[/tex]
[tex]\bf 3.\\ \\ \it f=\Big(\dfrac{2}{3}\Big)^2\cdot\Big(\dfrac{2}{3}\Big)^3\cdot\Big(\dfrac{2}{3}\Big)^3-\Big(\dfrac{1}{6}\Big)^2=\dfrac{4}{9}\cdot\Big(\dfrac{2}{3}\cdot\dfrac{3}{2}\Big)^3 -\dfrac{1}{36}=\dfrac{^{4)}4}{\ 9}-\dfrac{1}{36}=\\ \\ \\ =\dfrac{\ \ 15^{(3}}{36}=\dfrac{^{2)}5}{\ 12}=\dfrac{10}{24}[/tex]