\(e,=-\left(x-y\right)^7:\left(y-x\right)^5=-\left(x-y\right)^2\\ f,=\left(x-y\right)^7:\left(x-y\right)^4=\left(x-y\right)^3\\ g,=\left[-3\left(2a-b\right)\right]^3:\left[9\left(2a-b\right)\right]\\ =\left[-27\left(2a-b\right)^3\right]:\left[9\left(2a-b\right)\right]\\ =-3\left(2a-b\right)^2\\ h,=\dfrac{27a^6b^3\cdot4a^2b^6}{a^8b^8}=108b\)