已知1/x=1/y+4,求分式(6x+3xy-6y)/(x-y-2xy)的值?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/11 05:39:01
已知1/x=1/y+4,求分式(6x+3xy-6y)/(x-y-2xy)的值?

已知1/x=1/y+4,求分式(6x+3xy-6y)/(x-y-2xy)的值?
已知1/x=1/y+4,求分式(6x+3xy-6y)/(x-y-2xy)的值?

已知1/x=1/y+4,求分式(6x+3xy-6y)/(x-y-2xy)的值?
1/x=1/y+4 两边乘以xy
y=x+4xy
x-y=-4xy
(6x+3xy-6y)/(x-y-2xy)
=[6(x-y)+3xy]/(x-y-2xy)
=(-24xy+3xy)/(-4xy-2xy)
=-21/(-6)
=7/2
祝开心

(6x+3xy-6y)/(x-y-2xy)分子分母同时除以xy
=(6/y+3-6/x)/(1/y-1/x-2)
因为1/x=1/y+4
则1/y-1/x=-4
原式=【6*(-4)+3】/【-4-2】=-21/-6=7/2

由1/x=1/y+4得
y=x+4xy,y-x=4xy
因此
6x+3xy-6y=3xy-6*4xy=-21xy
x-y-2xy=-4xy-2xy=-6xy
所以,原式=21/6=7/2=3.5


由条件式变形得:x-y=-4xy
代人整理、化简的原式
=[6﹙x-y﹚+3xy]/[﹙x-y﹚-2xy]
=[6×﹙-4xy﹚+3xy]/[-4xy-2xy]
=21/6
=7/2。

7/2


1/x=1/y+4
1/x-1/y=4
(y-x)/xy=4
y-x=4xy
则:(6x+3xy-6y)/(x-y-2xy)
=[6(x-y)+3xy]/[(x-y)-2xy]
=[6(-4xy)+3xy]/[(-4xy)-2xy]
=(-21xy)/(-6xy)
=21/6
=7/2