已知1÷y-1÷x=5,求(2x+4xy-2y)÷(x-3xy-y)的值

问题描述:

已知1÷y-1÷x=5,求(2x+4xy-2y)÷(x-3xy-y)的值

1/y - 1/x =5
所以:x/xy - y/xy =5
即是:(x-y)/xy =5
x-y =5xy
(2x+4xy-2y)/ (x-3xy-y)
=((2x-2y)+4xy )/((x-y)-3xy)
=(2*5xy+4 xy)/(5xy-3xy)
=14 / 2
=7