用十字相乘法因式分解5-7(a+1)-6(a+1)^2-4x^3 +6x^2 -2x6(y-z)^2 +13(z-y)+6

1,(-2a-1)(3a+8)
2,-2x(2x-1)(x-1)
3,(3z-3y+2)(2z-2y+3)

5-7(a+1)-6(a+1)^2
=[1-2(a+1)][5+3(a+1)]
=(1-2a-2)(5+3a+3)
=(-2a-1)(3a+8)
-4x^3 +6x^2 -2x
=-2x(2x^2-3x+1)
=-2x(x-1)(2x-1)
6(y-z)^2 +13(z-y)+6
=6(z-y)^2+13(z-y)+6
=[2(z-y)+3][3(z-y)+2]
=(2z-2y+3)(3z-3y+2)

5-7(a+1)-6(a+1)^2
=-[6(a+1)^2+7(a+1)-5]
=-[2(a+1)-1][3(a+1)+5]
=-(2a+1)(3a+8);
-4x^3 +6x^2 -2x
=-2x(2x^2-3x+1)
=-2x(x-1)(2x-1);
6(y-z)^2 +13(z-y)+6
=6(z-y)^2+13(z-y)+6
=[2(z-y)+3][3(z-y)+2]
=(2z-2y+3)(3z-3y+2).

1 (-2(a+1)+1)(3(a+1)+5)
2 -x(2x-1)(2x-2)
3 (2(z-y)+3)(3(z-y)+2)