Giải:
\(a,27^3:3^2.\)
\(=\left(3^3\right)^3:\left(3^1\right)^2.\)
\(=3^9:3^2.\)
\(=3^{9-2}=3^7.\)
Vậy-.
\(b,\left(\dfrac{3}{5}\right)^{13}:\left(\dfrac{9}{25}\right)^5.\)
\(=\left(\dfrac{3}{5}\right)^{13}:\left[\left(\dfrac{3}{5}\right)^2\right]^5.\)
\(=\left(\dfrac{3}{5}\right)^{13}:\left(\dfrac{3}{5}\right)^{10}.\)
\(=\left(\dfrac{3}{5}\right)^{13-10}.\)
\(=\left(\dfrac{3}{5}\right)^3.\)
Vậy-.
~ Hok tốt!!! ~ =))