已知1／x＋1／y=4,求﹙4x-2xy＋4y﹚／﹙x＋3xy＋y﹚

已知1／x＋1／y=4,求﹙4x-2xy＋4y﹚／﹙x＋3xy＋y﹚
已知1／x＋1／y=4,求﹙4x-2xy＋4y﹚／﹙x＋3xy＋y﹚

已知1／x＋1／y=4,求﹙4x-2xy＋4y﹚／﹙x＋3xy＋y﹚
1／x＋1／y=4
(x+y)/xy=4
x+y=4xy
﹙4x-2xy＋4y﹚／﹙x＋3xy＋y)
=[4(x+y)-2xy]/(x+y+3xy)
=(16xy-2xy)/(4xy+3xy)
=14xy/7xy
=2
愿对你有所帮助!

4x-2xy+4y/x+3xy+y
分子分母同时处以xy的
=[4/y-2+4/x]/[1/y+3+1/x]
=[4(1/x+1/y)-2]/[(1/x+1/y)+3]
=(4×4-2)/(4+3)
=14/7
=2

﹙4x-2xy＋4y﹚／﹙x＋3xy＋y﹚(分子分母同除以xy)
=(4/y+4/x-2)/(1/y+1/x+3)
=[4(1/x+1/y）-2]/(4+3)
=14/7
=2
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