[tex] \left(\dfrac{7\cdot3\cdot2}{7\cdot5}\right)^2\times\left(\dfrac{7^0}{5^{-3}}\right)\times5^{-9}\\\\=\left(\dfrac{6}{5}\right)^2\times\left(\dfrac{1}{5^{-3}}\right)\times5^{-9}\\\\=\dfrac{6^2}{5^2}\times\dfrac{5^{-9}}{5^{-3}}=6^2\times5^{-9-(-3)-2}=36\times5^{-8}=\dfrac{36}{5^8}\\\\\text{Used}\\\\\left(\dfrac{a}{b}\right)^n=\dfrac{a^n}{b^n}\\\\\dfrac{a^n}{a^m}=a^{n-m}\\\\a^{-n}=\dfrac{1}{a^n} [/tex]
