UC知道1/x+1/y=5,求(2x-3xy+2y)/(x+2xy+y^2)的值？
来源：百度知道 编辑：UC知道 时间：2024/05/25 17:19:08
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题目抄错了！(2x-3xy+2y)/(x+2xy+y)！
1/x+1/y=(x+y)/xy=5
x+y=5xy
(2x-3xy+2y)/(x+2xy+y)
=(10xy-3xy)/(5xy+2xy)
=1.
1/x+1/y=5=（x+y）/xy, 5xy=x+y
代入，所求式=7xy/(x+y)^2 = 7/25 =0.28
1/x+1/y=(x+y)/xy=5
x+y=5xy
(2x-3xy+2y)/(x+2xy+y^2)
错了吧
应该是(2x-3xy+2y)/(x+2xy+y)
=[2(x+y)-3xy]/[(x+y)+2xy]
=(10xy-3xy)/(5xy+2xy)
=7xy/7xy
=1