因式分解(1).am^2+am-bm^2-bm ( 2).a^3-a^2-a+1 (3).a^2-2ab+b^2+a-b (4).9x^2-z^2+y^2-6xy(5).(x+y)^2-3(x+y)+2 (6)x^2-7x+10 (7).x^2-9x+18 (8).x^2-5x-6

我觉得是 （1）（am+bm)[(am+bm)+1]
(2) (a+1)(a-1)²
(3) (a-b)[(a+b)+1]
(4) [(y-3x)+z][(y-3x)-z]
(5) [(x+y-1][(x+y+1]
(6) (x-2)(x-5)
(7) (x-3)(x-6)
(8) (x+1)(x-6)

(1).am^2+am-bm^2-bm=m(a-b)(m+1)
(2).a^3-a^2-a+1=(a+1)(a-1)²
(3).a^2-2ab+b^2+a-b=(a-b)(a-b+1)
(4).9x^2-z^2+y^2-6xy=(3x-y+z)(3x-y-z)
(5).(x+y)^2-3(x+y)+2=(x+y-1)(x+y-2)
(6)x^2-7x+10=(x-2)(x-5)
(7).x^2-9x+18=(x-3)(x-6)
(8).x^2-5x-6=(x+1)(x-6)