已知x-y=3xy,求分式3x+2xy-3y/x-2xy-y的值

问题描述:

已知x-y=3xy,求分式3x+2xy-3y/x-2xy-y的值

11
把3xy=x-y带进去就可以了

=9xy+2xy/3xy-2xy
=11xy/xy
=11