(x-y)²+4(x-y)+3

问题描述:

(x-y)²+4(x-y)+3

(x-y)²+4(x-y)+3
=(x-y+3)(x-y+1)

:(x-y)²+4(x-y)+3=(x-y+2)²-1=(x-y+1)(x-y+3)