已知|2m-5|+(2m-5n+20)^2=0,求(-2m^2)-2m(5n-2m)+3n(6m-5n)-3n(4m-5

已知m/n=5、,求（m/（m+n）)+(m/(m-n))-(n^2/(m^3-n^2)) （n-m)^3×(m-n)^2-(m-n)^5 因式分解(n-m)^3(m-n)^2-(m-n)^5 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-5n=0,求m/(m+n)+m/(m-n)-m^2/(m^2-n^2)的值 已知3m-5n=0求m/m+n+m/m-n-m^2/m^2-n^2的值 如果m,n互为相反数,求m+2m+3m+4m+5m+5n+4n+3n+2n+n=多少 [2(m+n)^5-3(m+n)^4+(-m-n)^3]÷[2(m+n)^3] (m-5n)(m-n)-6(m+2n)(m-3n) 已知m-2n=3.求[(3m+2n)(3m-2n)-(m+2n)(5m-2n)]÷1/3 m 的值. 在线等已知m/n=5/3,求m/(m+n)+m/(m-n)-n^2/(m^2-n^2)... 已知m/n=5/3,求分式m/(m+n)+m/(m-n)-n^2/(m^2-n^2)的值