\(a,\dfrac{\left(-3\right)^{10}.15^5}{25^3.9^7}=\dfrac{3^{10}.\left(3.5\right)^5}{\left(5^2\right)^3.\left(3^2\right)^7}=\dfrac{3^{10}.3^5.5^5}{5^6.3^{14}}=\dfrac{3^{10+5}.5^5}{5^6.3^{14}}=\dfrac{3^{15}.5^5}{5^6.3^{14}}=\dfrac{3}{5}\)
cs phần nào chưa hiểu thì hỏi mình nha .CHÚC BN HC TỐT !