[-(xy)/(x-y)^2]^4*[(x^2-xy)/x]^3*x^4/y^10÷[x/(xy-y^2)]^5
=(x^4y^4)/(x-y)^8*(x-y)^3*x^4/y^10*[y^5(x-y)^5]/x^5
=x^3/y
代入x=-2,y=4,
原式=(-2)^3/4=-2.