已知1/x+1/y=3,求(3x-5xy+3y)/(x-2xy+y)
问题描述:
已知1/x+1/y=3,求(3x-5xy+3y)/(x-2xy+y)
答
1/x+1/y=3 去分母得 x+y=3xy
(3x-5xy+3y)/(x-2xy+y)
=[3(x+y)-5xy]/(x+y-2xy)
=(9xy-5xy)/(3xy-2xy)
=4xy/xy=4