初一因式分解，赶快

1.（9a^2-b^2)/(3a-b)
=(3a+b)(3a-b)/(3a-b)
=3a+b

2.(x^2+13x+42)/(x+6)
=(x+6)(x+7)/(x+6)
=x+7

3.(3m^2-5m-2)/(3m+1)
=(3m+1)(m-2)/(3m+1)
=m-2

4.(x^2-y^2+2x+1)/(x-y+1)
=[(x+1)^2-y^2]/(x-y+1)
=(x-y+1)(x+y+1)/(x-y+1)
=x+y+1

5.(3x^3*y^2+6x^2*y^3)/(x+2y)
=3x^2y^2(x+2y)/(x+2y)
=3x^2y^2

6.(2-32a^4)/(4a^2+1)/(2a+1)
=2(1-16a^4)/[(4a^2+1)(2a+1)]
=2(1-4a^4)(1+4a^2)/[(4a^2+1)(2a+1)]
=2(1-2a)(1+2a)/[(4a^2+1)(2a+1)]
=2(1-2a)
=2-4a

7.解方程x^3-9x=0
x(x-9)=0
x1=0,x2=9

8.解方程x^3-4x=x^2-4
x(x^2-4)-(x^2-4)=0
(x^2-4)(x-1)=0
(x+2)(x-2)(x-1)=0
x1=-2,x2=2,x3=1

9.已知（a^2+b^2)*(a^2+b^2-1)=6,求a^2+b^2的值
令m=a^2+b^2
则a*(a-1)=6
a^2-a-6=0
(a-3)(a+2)=0
a1=3,a2=-2
因为x^2+y^2>=0
所以a2=-2舍去
所以x^2+y^2=a1=3

10.若二次三项式x^2+ax-1可分解成（x-2)(x+b)求(a+b)的值
(x-2)(x+b)
=x^2-2