X分之1加Y分之1＝2,则2X减XY加2Y除以3X加5XY加3Y＝?一道数学题很简单的考考你们步骤也要_其他解答

X分之1加Y分之1＝2,则2X减XY加2Y除以3X加5XY加3Y＝?
一道数学题很简单的考考你们步骤也要

人气：455 ℃　时间：2020-05-08 06:37:13

解答

1/x+1/y=2
(x+y)/xy=2
x+y=2xy
(2x-xy+2y)/(3x+5xy+3y)
=[2(x+y)-xy]/[3(x+y)+5xy]
=(4xy-xy)/(6xy+5xy)
=3xy/11xy
=3/11