2.(x- 1)2-2(x- 1)+ 1

Solution: The original formula =(x- 1- 1)2.

=(x-2)2。

3.8x2- 10x+2

Solution: Original formula =2(4x2-5x+ 1)

=2(4x- 1)(x- 1)

=(4x- 1)(2x-2)

4.2a2-4a

Solution: Original formula =2a(a-2)

5.4x2-4x+ 1=(2x- 1)2

6.a4b-6a3b+9a2b

Solution: Original formula =a2b(a2-6a+9)

=a2b(a-3)2

7.x(x-y)-y(x-y)=(x-y)2

8.x2y-4y

Solution: Original formula =y(x2-4)

=y(x2-22)

=y(x+2)(x-2)

9.2x2-4x+2

Solution: Original formula =2(x2-2x+ 1)

=2(x- 1)2

10.m2- 16=(m-4)(m+4)

1 1.m2+4m=m(m+4)

12.m2-8m+ 16=(m-4)2

13 . a2-2a+ 1 =(a- 1)2

14 . x2+2x+ 1 =(x+ 1)2

15.x2-y2-2y- 1

Solution: The original formula =x2-(y2+2y+ 1),

=x2-(y+ 1)2，

=(x+y+ 1)(x-y- 1)

16.(6x2-3x)-2(7x-5)，

Solution: The original formula =6x2-3x- 14x+ 10.

=(6x-5)(x-2)

17.a3-4ab2

Solution: Original formula =a(a2-4b2)

=a(a+2b)(a-2b)

18.x3-2x2+x

Solution: Original formula =x(x2-2x+ 1)

=x(x- 1)2

19.x2-6x+9=(x-3)2

20.mx2-6mx+9m，

Solution: The original formula =m(x2-6x+9),

=m(x-3)2

Sorry, I've been playing for about 20 minutes. I'm so tired. You can go to Jingyu. Com and search. There is a lot of analysis in it.