已知1/x=1/y=6,则3x-2xy+3y/3xy+x+y=?已知1/x+1/y=6,则3x-2xy+3y/3xy+x+y=?

已知1/x=1/y=6,则3x-2xy+3y/3xy+x+y=?已知1/x+1/y=6,则3x-2xy+3y/3xy+x+y=? 已知1/X+1/Y=6,则3X-2XY+3y/3XY+X+Y=多少 已知2/X-1/Y=3,则(X-2Y-XY)/(5XY+6Y-3X)=? 已知2/x-1/y=3,则(2y-x+4xy)/(3x-6y-5xy)=? 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 已知x+y=1,xy=-2,则x²y+xy²-2xy 已知x-y=6,xy=-1,求(2x+3x-2xy)-(x+4y+xy)-(3yx-2x+2y)的值 已知1/x-1/y=-3,则x+3xy-y/3x-2xy-3y= 已知1/x=3+1/y,则(2x-5xy-2y)/(y+3xy-x)=_______. 已知1/x+1/y=3,则2x-3xy+2y/x+xy+y=谢谢了, 已知1/x-1/y=-3,则x+5xy-y/3x-2xy-3y= 已知1/x-1/y=5,则2x+3xy-2y/y+2xy-x 已知1/x减1/y=-3,则(2x+xy-2y)/x-xy-y的值为 已知1/X-1/Y=5 ,则x-2xy-y/4x+3xy-4y 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3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y) (1)已知x+y=6,xy=-3,x^2y+xy^2=(2)x*[2-(1/x)]+(x/x^2-2x)*(x^2-4) .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值