X分之1加Y分之1＝2,则2X减XY加2Y除以3X - 知识问答

X分之1加Y分之1＝2,则2X减XY加2Y除以3X加5XY加3Y＝?

5个回答

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

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