a) \(9^8\div\left(27^3\times81^2\right)=\left(3^2\right)^8\div\left[\left(3^3\right)^3\times\left(3^4\right)^2\right]\)= \(3^{16}\div\left(3^9\times3^8\right)=3^{16}\div3^{17}=\frac{1}{3}\)
b) \(\left(125^4\times7^{10}\right)\div\left(5^{12}\times343^3\right)=\left[\left(5^3\right)^4\times7^{10}\right]\div\left[5^{12}\times\left(7^3\right)^3\right]\)= \(\frac{5^{12}\times7^{10}}{5^{12}\times7^9}=7\)