计算(x-3y+2z)(-x-3y-2z)要有过程哈·
问题描述：
计算(x-3y+2z)(-x-3y-2z)
要有过程哈·
答
(x-3y+2z)(-x-3y-2z)
=-(x-3y+2z)(x+3y+2z)
=-[(x+4z)^2-(3y)^2]
=9y^2-(x+4z)^2
=9y^2-(x^2+4xz+4z^2)
=9y^2-x^2-4xz-4z^2
答
(x-3y+2z)(-x-3y-2z)＝－[x+2z-(3y)][x＋2z+(3y)]=-(x+2z)^2+9y^2=9y^2-x^2-4z^2-4xz