xy/(x+y) = 2得：xy=2(x+y)
(3x-5xy+3y)/(-x+3xy-y)
=(3x-9xy+3y+4xy)/(-x+3xy-y)
= -3 + 4xy/(-x+3xy-y)
= -3 + 8(x+y)/(-x+6x+6y-y)
= -3 + 8(x+y)/5(x+y)
= -3 + 8/5
= -7/5
祝你学习进步，更上一层楼！ (*^__^*)
将x＋y换掉。最后xy都约了。就是这个答案
已知x加y分之xy等于2,求负x加3xy减y分之3x减5xy加3y
xy\/(x+y) = 2得：xy=2(x+y)(3x-5xy+3y)\/(-x+3xy-y)=(3x-9xy+3y+4xy)\/(-x+3xy-y)= -3 + 4xy\/(-x+3xy-y)= -3 + 8(x+y)\/(-x+6x+6y-y)= -3 + 8(x+y)\/5(x+y)= -3 + 8\/5 = -7\/5 祝你学习进步，更上一层楼！ (*^__^*)...
已知x加y分之xy等于2,求负x加3xy减y分之3x减5xy加3y?
xy\/(x+y) = 2得：xy=2(x+y)(3x-5xy+3y)\/(-x+3xy-y)=(3x-9xy+3y+4xy)\/(-x+3xy-y)= -3 + 4xy\/(-x+3xy-y)= -3 + 8(x+y)\/(-x+6x+6y-y)= -3 + 8(x+y)\/5(x+y)= -3 + 8\/5 = -7\/5,6,将x＋y换掉。最后xy都约了。就是这个答案 ,1,
已知x+y分之xy=2,求-x+3xy-y分之3x-5xy+3y的值
xy\/(x+y)=2 xy=2x+2y (-x+3xy-y)分之(3x-5xy+3y)=(3x-5xy+3y)\/(-x+3xy-y)=[3x-5(2x+2y)+3y)\/[-x+3(2x+2y)-y]=(3x-10x-10y+3y)\/(-x+6x+6y-y)=(-7x-7y)\/(5x+5y)=[-7(x+y)]\/[5(x+y)]=-7\/5 =-1.4 ...
已知x+y分之xy=2,求代数式-x+3xy-y分之-5xy+3x+3y的值
xy\/(x+y)=2 得 1\/x+1\/y=1\/2 原式=[-5+3(1\/x+1\/y)]\/[3-(1\/x+1\/y)]=(-5+3\/2)\/(3-1\/2)=-7\/5
已知xy分之x加y等于2,求3x减5xy加3y分之负x加3xy减y.急快...
xy分之x加y等于2 ∴x+y=2xy 3x减5xy加3y分之负x加3xy减y =[-(x+y)+3xy]\/[3(x+y)-5xy]=(-2xy+3xy)\/(6xy-5xy)=xy\/(xy)=1
以知x+y分之xy=2,求代数式-x+2xy-y分之3x-5xy+3y的值
由xy\/（x+y）=2，∴xy=2（x+y）∵（-x+2xy-y）\/（3x-5xy+3y）=（-x-y+4x+4y）\/3x+3y-10x-10y）=（3x+3y）\/（-7x-7y）=-3\/7.
已知x+y分之xy=3求-2x+3xy-2y分之3x-5xy+3y的ŀ
因为xy=3(x+y)所以原式=-2（x+y)+3xy分之3（x+y)-5xy=-1.5xy+3xy分之xy-5xy=-3分之8
已知xy除以x+y=2,求代数式3x-5xy+3y除以﹣x+3xy-y的值
xy\/（x+y）=2 , xy=2（x+y）(x-5xy+3y)\/(﹣x+3xy-y)=(x-5*2（x+y）+3y)\/(﹣x+3*2（x+y）-y)=(3x-10x-10y+3y)\/(-x-6x-6y-y)=(-7x-7y)\/(-7x-7y)=1
如果XY\/X+Y=2,求代数式3X-5Y+3Y\/-X+3XY-Y的值为 ?没错!
"确定题目没错 分子的"-5Y"和"+3Y"是同类项 若是"代数式3X-5XY+3Y\/-X+3XY-Y的值为 "则答案是 3X-5XY+3Y\/-X+3XY-Y =（3X-5XY+3Y）\/（-X+3XY-Y）=[3(X+Y)\/(XY)-5]\/[3-（X+Y)\/(XY）]=(3\/2-5)\/(3-1\/2)=-7\/5 =-1.4 ...
已知1\/x+1\/y=2 则分式3x-5xy+3y\/x+3xy+y=?
解：∵1\/x+1\/y=2 ∴x+y\/xy=2 x+y=2xy 3x-5xy+3y\/x+3xy+y =3(x+y)-5xy\/(x+y)+3xy =3×2xy-5xy\/2xy+3xy =xy\/5xy =1\/5
