计算(x-2y+3)平方-(x-2y+3)(x-2y-3)

问题描述:

计算(x-2y+3)平方-(x-2y+3)(x-2y-3)

(x-2y+3)平方-(x-2y+3)(x-2y-3)
=(x-2y+3)(x-2y+3-x+2y+3)
=6(x-2y+3)
=6x-12y+18