设m和n均不为0,3x^2y^m+n和-5x^m y^3是同类项,求3m^3-m^2n+3mn^2+9n^3/5m^3+3m^2n-6mn^2+9n^3

设m和n均不为0,3x^2y^m+n和-5x^m y^3是同类项,求3m^3-m^2n+3mn^2+9n^3/5m^3+3m^2n-6mn^2+9n^3
设m和n均不为0,3x^2y^m+n和-5x^m y^3是同类项,求3m^3-m^2n+3mn^2+9n^3/5m^3+3m^2n-6mn^2+9n^3

设m和n均不为0,3x^2y^m+n和-5x^m y^3是同类项,求3m^3-m^2n+3mn^2+9n^3/5m^3+3m^2n-6mn^2+9n^3
同类项,故：2=m；m+n=3
得到：m=2 n=1
代入即可