原式=1/8×m^-4 n^6×m^2n^-4×1
=1/8(m^-2n^2)
=n^2/(8m^2)额、错了、最后答案应该是：n^5/8m^4哦，对不起原式=1/8×m^-6 n^9×m^2n^-4×1=1/8(m^-4n^5)=n^5/(8m^4)