①a²-b²-2b-1 ②a四次方-9-6b-b² ③ x三次方+2xy-x-xy²

①a²-b²-2b-1=a²-（b²+2b+1）=a²-(b+1)²=(a+b+1)(a-b-1)
②a四次方-9-6b-b²=a四次方-(9+6b+b²)=a四次方-(b+3)²=(a²+b+3)(a²-b-3)
③ x三次方+2xy-x-xy²=x(x²+2y-1-y²)=x[x²-(y²-2y+1)]=x[x²-(y-1)²]=x(x+y-1)(x-y+1)

①a²-b²-2b-1
=a²-(b+1)²
=(a+b+1)(a-b-1)
②a四次方-9-6b-b²
=a^4-(3+b)²
=(a²-3-b)(a²+3+b)
③ x三次方+2xy-x-xy²
=x(x²-y²-1+2y)
=x[x²-(y-1)²]
=x(x-y+1)(x+y-1)
我同样上七年级，同胞啊·······希望能帮到你，求采纳，O(∩_∩)O谢谢

①a²-b²-2b-1
=a²-(b+1)²
=(a+b+1)(a-b-1)
②a四次方-9-6b-b²
=a^4-(3+b)²
=(a²-3-b)(a²+3+b)
③ x三次方+2xy-x-xy²
=x(x²-y²-1+2y)
=x[x²-(y-1)²]
=x(x-y+1)(x+y-1)