(1) 6x4y2-12x3y+27x2y3=3x2y·2x2y-3x2y·4x+3x2y·9y2=3x2y(2x2y-4x+9y2)(2)-x4y+x3y2-x2y3=-(x4y-x3y2+x2y3)=-(x2y·x2-x2y·xy+x2y·y2)=-x2y(x2-xy+y2)(3)xn+3xn-1+xn-2=xn-2·x2+xn-...
(1) 6x4y2-12x3y+27x2y3=3x2y·2x2y-3x2y·4x+3x2y·9y2=3x2y(2x2y-4x+9y2)(2)-x4y+x3y2-x2y3=-(x4y-x3y2+x2y3)=-(x2y·x2-x2y·xy+x2y·y2)=-x2y(x2-xy+y2)(3)xn+3xn-1+xn-2=xn-2·x2+xn-...