已知2x-3xy=6,3xy-2y=-2,则x-y=?
问题描述:
已知2x-3xy=6,3xy-2y=-2,则x-y=?
答
∵ 2x-3xy=6,3xy-2y=-2
∴ (2x-3xy)+(3xy-2y)=6+(-2) (两式相加)
==>2x-2y=4
==>2(x-y)=4
故 x-y=2