x^2-2xy=3xy-6y^2,求x/y的值(y不为0)

已知xy/x+y=6,求3x-2xy+3y/-x+3xy-y的值. 已知(xy)/(x+y)=6求(3x-2xy+3y)/(-x+3xy-y)的值. 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 已知:x/y=-2,求x^2-2xy-3y^2/x^-6xy x^+2xy+y^+4=16 x^-2xy+y^=16 求(3xy+6y^)+|x^-(2xy+2y^-3x^)|的值 1-2/x+y=xy,4y+6x=xy.求xy的解? 当x-y=2xy时,求4x-3xy-4y/xy 已知x/y=2,求 [x^2-xy+3xy^2 ] / [ x^2+xy+6y^2]的值 3X^2+XY+Y=15 求XY. 已知x:y=3:2,求(x²+3xy)/(xy+2xy) 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 X-Y方=6 XY=2 求 3x²y-xy的立方 已知x+y=4,xy=-2,求代数式3(xy+2y)-(xy-6x)的值 已知x+y=4,xy=-2,求代数式3（xy+2y）-（xy-6x） 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 x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值 已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值.