Ta có:
\(\dfrac{5^4.20^4}{25^5.4^5}=\dfrac{5^4.5^4.4^4}{\left(5^2\right)^5.4^5}=\dfrac{5^8.4^4}{5^{10}.4^5}=\dfrac{1}{5^2.4}=\dfrac{1}{25.4}=\dfrac{1}{100}=0,01\)
\(\dfrac{5^4.20^4}{25^5.4^5}=\dfrac{5^4.\left(4.5\right)^4}{\left(5.5\right)^5.4^5}=\dfrac{5^4.4^4.5^4}{5^5.5^5.4^5}=\dfrac{1}{5.5.4}=\dfrac{1}{100}\)
\(\dfrac{5^4.20^4}{25^5.4^5}=\dfrac{5^4.\left(5.4\right)^4}{\left(5^2\right)^5.4^5}=\dfrac{5^4.5^4.4^4}{5^{10}.4^5}=\dfrac{5^8.4^4}{5^8.5^2.4.4^4}=\dfrac{1}{100}\)