æ以xy=2(x+y)
(3x-5xy+3yï¼Ã·ï¼-x+3xy-yï¼
=(3x-10[x+y]+3y)÷(-x+6[x+y]-y)
=(-7x-7y)÷(5x+5y)
=-7/5
xy÷x+y=2求代数式三x+ay-5 xy÷-x-3 xy减y的值
比较简单,利用已知：XY÷（x+y)=2,可得出XY=2(X+Y),对需计算式,简单化简.将式中XY换成 2(X+Y),即可.但是需要注意分母中的符号.
已知xy除以x+y=2,求代数式3x-5xy+3y除以﹣x+3xy-y的值
(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
已知xy\/x+y=2,求代数式3x-5y+3y\/-x+3xy-y的值
因为xy\/（x+y）=2 →(x+y)=xy\/2 则（3x-5y+3y）\/（-x+3xy-y）=[3(x+y)-5y]\/[-(x+y)+3xy]=[3*(xy\/2)-5y]\/[-xy\/2 +3xy]=(3xy\/2 -5y)\/(5xy\/2)=3\/5-2\/x
已知xy\/x+y=2,求3x-5x+3y\/-x+3xy-y的值。
=[3(x+y)-5xy]\/[-(x+y)+3xy]=(3\/2xy-5xy)\/(-1\/2xy+3xy)=(3\/2-5)\/(3-1\/2)=-7\/5 你是不是分子分母写倒了 呵呵 若是xy 是分母 x+y是分子 (x+y)\/xy=2 x+y=2xy (-x+3xy-y)\/(3x-5xy+3y)=[-(x+y)+3xy]\/[3(x+y)-5xy]=(-2xy+3xy)\/(6xy-5xy)=xy\/...
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 ...
...X+Y等于2 求代数式3X--5XY+3Y除以(--X+3XY--Y) 提示把XY 和 X+Y...
（3X--5XY+3Y）\/(--X+3XY--Y)=【3（X+Y）-5XY】\/【3XY-（X+Y）]上下同时除以（X+Y)得出：【3-5XY\/（X+Y)】\/3XY\/（X+Y)-1 =（3-10）\/（6-1）=-7\/5 XY\/（X+Y)=2
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
已知 xy\/(x+y) = 2，求:(3x-5xy+3y)\/(-x+3xy-y)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...
如果xy\/x+y=2,那么3x-5xy+3y\/-x+3xy-y=?
xy\/x+y=2，xy=2(x+y)3x-5xy+3y\/-x+3xy-y =(3(x+y)-10(x+y))\/(6(x+y)-(x+y))=-7\/5
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?
已知 xy\/(x+y) = 2,求:(3x-5xy+3y)\/(-x+3xy-y)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分之xy=2,求代数式-x+3xy-y分之3x-5xy+3y的值
x+y分之xy=2，则 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 ...
