｛2m+3n=3 ①4m-n=27② {3y=2x ①3x-2y=-5② 现在要 急

已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2= (m-2n)(2n+m)-(-3m-4n)(4n-3m)= .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-[n-3m-(m-n)]=? 已知m=1/3,n=1/27,求m-n/根号m-根号n+(m+4n-4根号mn)/根号m-2根号n 已知3m=2n,则m/(m+n)+n/(m-n)-n^2/(m^2-n^2)=? (m-2n)^2+(3m-n)(2m+2n)-(2m+n)(2m-n) 已知m+n=4 mn=1 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 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)) 解二元一次方程组!（m+n）/3 - （m-n）/4=0.35 ① （m+n）/3 + （m-n）/2=0.5 ② |m-n|=n-m,且|m|=4,|n|=3,则m+n=? 2m+3n+2m+3n+m+2m+3n+n=______ (m+4)^2+|n+3|=01/2m-n 1若m=n,则|m|=|n|;2若m=—n,则|m|=|n|;3若|m|=|n|,则m=—n;4若|m|=|n|,则m=n哪个对