｛m-2/n=5,｛2m+3n=12； 用代入消元法解这个方程组

m/n=5/3,求（m/m+n）+（m/m+n)-（n^2/m^2-n^2) 已知m/n=5、,求（m/（m+n）)+(m/(m-n))-(n^2/(m^3-n^2)) .4（m+n)^2*（m+n)^3-7（m+n)（m+n)^4+5（m+n)^5= (m-n)^3(n-m)^2(m-n)=_____ (3m-n)(m-2n)=() (m-2n/n-m)-(n/m-n)= m-{n-2m+[3m-(6m+3n)+5n]}= 已知3m=2n,则m/(m+n)+n/(m-n)-n^2/(m^2-n^2)=? 若2m-n/m+2n=5,求3（2m-n）/m+2n-m+2n/2m-n+3的值 若2m-n/m+2n=5,求3（2m-n）/m+2n-m+2n/2m-n+3的值 诺2m-n/m+2n=5,求3(2m-n)/m+2n-m+2n/2m-n+3的值 已知m-2n/2m+n=5,求代数式3(m-2n)/2m+n－15(2m+n)/m-2n－2 已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2= 如果m和n互为相反数,则m+2m+3m+4m+5m+5n+4n+3n+2n+n= 如果m,n互为相反数,求m+2m+3m+4m+5m+5n+4n+3n+2n+n=多少 2m+3n+2m+3n+m+2m+3n+n=______ 已知|m|=5,|n|=2 |m+n|=m+n,求m-n (m-2n)(2n+m)-(-3m-4n)(4n-3m)=