要求详解,不要照抄答案,给30分

1.解法1.x^3-9x+8
=x^3-1-9x+9
=(x-1)(x^2+x-8)
解法2.x^3-9x+8
=x^3-x-8x+8
=(x-1)(x^2+x-8)
解法3.x^3-9x+8
=9x^3-8x^3-9x+8
=(x-1)(x^2+x-8)
解法4.x^3-9x+8
=x^3-x^2+x^2-9x+8
=x^2(x-1)+(x-8)(x-1)
3.xy+y^2+x-y-2
=(xy+x)+(y^2-y-2)
=x(y+1)+(y-2)(y+1)
=(y+1)(x+y-2)