(-2/3x^2y^3)^3·(3xy)^2-(-1/2x^4y^3)^2·4/3y^4=-8/27x^6y^9·9x^2y^2-1/4x^8y^6·4/3y^4=-8/3x^8y^11-1/3x^8y^102/3（x-y)^3·9/4(x-y)^5·7/15(y-x)^8=2/3*9/4*7/15（x-y)^3*x-y)^5*(x-y)^8=7/10（x-y)^16