因式分解,急

9(x-y)(x+y)-z(z+6y)
x^3+8y^3-x^2+2xy-4y^2
6x-6y-9x^2+18xy-9y^2-1
(x^2+5x+4)(x^2+5x)+6(x^2+5x)+24
(a+b-2ab)(a+b-2)+(1-ab)^2

1. 9(x-y)(x+y)-z(z+6y)
=9x²-(9y²+6yz+z²)
=9x²-(3y+z)²
=(3x+3y+z)(3x-3y-z)

2. x^3+8y^3-x^2+2xy-4y^2
=(x+2y)(x^2-2xy+4y^2)-(x^2-2xy+4y^2)
=(x^2-2xy+4y^2)(x+2y-1)

3. 6x-6y-9x^2+18xy-9y^2-1
=-<9(x-y)^2-6(x-y)+1>
=-(3x-3y-1)^2

4. (x^2+5x+4)(x^2+5x)+6(x^2+5x)+24
= (x^2+5x)^2+4(x^2+5x)+6(x^2+5x)+24
=(x^2+5x+4)(x^2+5x+6)
=(x+1)(x+4)(x+2)(x+3)

5 (a+b-2ab)(a+b-2)+(1-ab)^2
=(a+b)^2-2(a+b)-2ab(a+b)+4ab+1-2ab+(ab)^2
=(a+b)^2-2(a+b)-2ab(a+b)+1+2ab+(ab)^2
=(a+b)^2-2(ab+1)(a+b)+(ab+1)^2
=(a+b-ab-1)^2

1. 9(x-y)(x+y)-z(z+6y)
=9x²-(3y+z)²
=(3x+3y+z)(3x-3y-z)

2. x^3+8y^3-x^2+2xy-4y^2
=(x+2y)(x^2-2xy+4y^2)-(x^2-2xy+4y^2)
=(x^2-2xy+4y^2)(x+2y-1)

3. 6x-6y-9x^2+18xy-9y^2-1
=-<9(x-y)^2-6(x-y)+1>
=-(3x-3y-1)^2