x^-1-y^-1=-3
即1/x-1/y=-3
(y-x)/xy=-3
y-x=-3xy
x-y=3xy
(2x+3xy-2y)÷(x-2xy-y)
=[2(x-y)+3xy]/[(x-y)-2xy]
=(6xy+3xy)/(3xy-2xy)
=9xy/xy
=9