1/x-1/y=3
(y-x)/(xy)=3
y-x=3xy
x-y=-3xy
(2x-14xy-2y)/(x-2xy-y)
=[2(x-y)-14xy]/[(x-y)-2xy]
=[2×(-3xy)-14xy]/[(-3xy)-2xy]
=(-20xy)/(-5xy)
=4你们答案不一样，我怎么知道你们谁对？是等于4的。