若(X^m/X^2n)^3/X^2(m-n)与2X^4是同类项,且m+5n=2(X^m/X^2n)^3/X^2(m-n)=(X^3m/X^6n)/X^2m*X^(-n)=X^3m*X^n/X^6n*X^2m=X^(3m-2m)*X^(n-6n)=X^m*X^(-5n)=X^(m-5n)根据题意,是同类项,得出,m-5n=4m+5n=2解出,m=3,n=-(1/5)M^2-25n=3^2-25*(-1/5)=9+5=14