根据题意有：
2+2m+n＝2
所以
2m+n＝0
所以
n=－2m
将n=－2m代入(3m^3-m^2n+3mn^2-6mn^2+9n^3)\(5m^3+3m^2n-6mn^2+9n^3)得：
(3m^3-m^2n+3mn^2-6mn^2+9n^3)\(5m^3+3m^2n-6mn^2+9n^3)
＝(－65m^3)/(－97m^3)
＝65/97