5) а) $$rac{125^3}{25^4}$$ б) $$rac{64^5}{128^4}$$ в) $$rac{81^6}{27^8}$$

5) а) $$rac{125^3}{25^4} = \frac{(5^3)^3}{(5^2)^4} = \frac{5^9}{5^8} = 5$$ б) $$rac{64^5}{128^4} = \frac{(2^6)^5}{(2^7)^4} = \frac{2^{30}}{2^{28}} = 2^2 = 4$$ в) $$rac{81^6}{27^8} = \frac{(3^4)^6}{(3^3)^8} = \frac{3^{24}}{3^{24}} = 1$$