XY/(100-X)=3/20 , 2XY/(100-2X=2/5 怎么解?

XY/(100-X)=3/20 , 2XY/(100-2X=2/5 怎么解? 因式分解x^3+2xy-x-xy^2= 化简:xy分之3x^2+2xy-xy分之2x^2-xy= （-3x^y+2xy)-( )=4x^+xy 3xy(x^2-xy^2+xy)-xy^2(2x^2-xy+2x) 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? 已知x:y=3:2,求(x²+3xy)/(xy+2xy) 当x-y=2xy时,求4x-3xy-4y/xy 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 已知xy+x=-3,xy-y=2求代数式-x-[2y-2(xy+x)^2+3x]+2[x+(xy-y)^2]的值 已知x^2-xy=10,xy-y^2=20,求：x^2-2xy+y^2 的值2x^2+xy-3y^2 的值2x^2-5xy+3y^2 的值 ( )-(x^2+3xy)=-xy-1/3y^2 ( )*3xy=6x^2y+2xy^2 2xy+5y^2+( )=x^2+3xy 3X^2+XY+Y=15 求XY. 因式分解X^3-2xy+xy^2 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2