计算:[x(x2y2-xy)-y(x2-x3y)]÷3x2y.

问题描述:

计算:[x(x2y2-xy)-y(x2-x3y)]÷3x2y.

原式=(x3y2-x2y-x2y+x3y2)÷3x2y
=(2x3y2-2x2y)÷3x2y
=

2
3
xy-
2
3