3^m=5 ,3^n=4,则3^(m-n)=?

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= |m-n|=n-m,且|m|=4,|n|=3,则m+n=? m/n=7/3则m+n/m-n .4（m+n)^2*（m+n)^3-7（m+n)（m+n)^4+5（m+n)^5= m-[n-3m-(m-n)]=? 已知3m=2n,则m/(m+n)+n/(m-n)-n^2/(m^2-n^2)=? 已知m/n=5/3,求m/(m+n)+m/(m-n)-n平方/(m平方-n平方) 已知m/n=5、,求（m/（m+n）)+(m/(m-n))-(n^2/(m^3-n^2)) m/n=5/3,求（m/m+n）+（m/m+n)-（n^2/m^2-n^2) 如果m,n互为相反数,求m+2m+3m+4m+5m+5n+4n+3n+2n+n=多少 (m-2n)(2n+m)-(-3m-4n)(4n-3m)= |m-n|=n-m,且|m|=4,|n|=3,求（m+n)*(m+n)的值 已知n/m=3/5,求m+n/m 若5m=-3n 则m ：n= |m-4|+|n+3|=0则m-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 (m-n)^3(n-m)^2(m-n)=_____