已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y
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)
是怎么变化的.请详细的说明一下.
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)
是怎么变化的.请详细的说明一下.
数学人气:828 ℃时间:2019-12-21 13:51:40
优质解答
因为x-y=-2xy所以将x-y都换成-2xy了
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