如果1\x-1\y=2,那么3x+5xy-3y\x-xy-y等于多少这是初二的数学题分式那一张的,有知道的请帮帮我,
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![如果1\x-1\y=2,那么3x+5xy-3y\x-xy-y等于多少这是初二的数学题分式那一张的,有知道的请帮帮我,](/uploads/image/z/559280-56-0.jpg?t=%E5%A6%82%E6%9E%9C1%5Cx-1%5Cy%3D2%2C%E9%82%A3%E4%B9%883x%2B5xy-3y%5Cx-xy-y%E7%AD%89%E4%BA%8E%E5%A4%9A%E5%B0%91%E8%BF%99%E6%98%AF%E5%88%9D%E4%BA%8C%E7%9A%84%E6%95%B0%E5%AD%A6%E9%A2%98%E5%88%86%E5%BC%8F%E9%82%A3%E4%B8%80%E5%BC%A0%E7%9A%84%2C%E6%9C%89%E7%9F%A5%E9%81%93%E7%9A%84%E8%AF%B7%E5%B8%AE%E5%B8%AE%E6%88%91%2C)
如果1\x-1\y=2,那么3x+5xy-3y\x-xy-y等于多少这是初二的数学题分式那一张的,有知道的请帮帮我,
如果1\x-1\y=2,那么3x+5xy-3y\x-xy-y等于多少
这是初二的数学题分式那一张的,有知道的请帮帮我,
如果1\x-1\y=2,那么3x+5xy-3y\x-xy-y等于多少这是初二的数学题分式那一张的,有知道的请帮帮我,
1/x-1/y=2
(y-x)/xy=2
y-x=2xy
(3x+5xy-3y)/(x-xy-y)
=[5xy-3(y-x)]/[-xy-(y-x)]
=(5xy-6xy)/(-xy-2xy)
=-xy/-3xy
=1/3
1/x-1/y=2
同时乘以xy
y-x=2xy
x-y=-2xy
[3(x-y)+5xy]/[(x-y)-xy]
=(-6xy+5xy)/(-2xy-xy)
=(-xy)/(-3xy)
=1/3
通分得y-x=2xy,将xy=(y-x)/2代入分式得[3(x-y)-5/2(x-y)]/[(x-y)+(x-y)/2] = 1/3