a)\(G=\frac{21^2.14.125}{35^5.6}=\frac{\left(3.7\right)^2.2.7.5^3}{\left(5.7\right)^5.2.3}=\frac{3^2.7^3.2.5^3}{5^5.7^5.2.3}=\frac{3}{5^2.7^2}=\frac{3}{35^2}=\frac{3}{1225}\)
b)\(H=\frac{45^3.20^4.18^2}{180^5}=\frac{\left(5.3^2\right)^3.\left(2^2.5\right)^4.\left(2.3^2\right)^2}{\left(5.3^2.2^2\right)^5}=\frac{5^3.3^6.2^8.5^4.2^2.3^4}{5^5.3^{10}.2^{10}}=\frac{5^7.2^{10}.3^{10}}{5^5.3^{10}.2^{10}}=5^2=25\)