若xy=2(x+y),求 (3x-5xy+3y)÷(-x+3xy-y) 的值

问题描述:

若xy=2(x+y),求 (3x-5xy+3y)÷(-x+3xy-y) 的值

(3x-5xy+3y)÷(-x+3xy-y)
=(3x+3y-10x-10y)÷(-x-y-6x-6y)
=-7(x+y)÷[-7(x+y)]
=1