12(x-y)-4-9(x-y)^2

问题描述:

12(x-y)-4-9(x-y)^2
分解因式

12(x-y)-4-9(x-y)²
=-[9(x-y)²-12(x-y)+4]
=-[3(x-y)+2]²
=-(3x-3y+2)²