(2X-3y)-(5x-y)

问题描述:

(2X-3y)-(5x-y)

(2X-3y)-(5x-y)
=2x-3y-5x+y
=2x-5x-3y+y
=(2x-5x)+(-3y+y)
=-3x-2y
这样写总是全过程了吧