分解因式（1-2a-a^2）b+a(a-1)(2b^2-1)

Question

分解因式（1-2a-a^2）b+a(a-1)(2b^2-1)

Answer 1

=b-2ab-a^2b+(a^2-a)(2b^2-1)
=b-2ab-a^2b+2a^2b^2-2ab^2-a^2+a
=(2b^2-b-1)a^2+(1-2b-2b^2)a+b
=(2b+1)(b-1)a^2+(1-2b-2b^2)a+b
2b+1 -1
b-1 -b
(2b+1)*(-b)+(b-1)*(-1)
=-2b^2-b-b+1
=-2b^2-2b+1
=[(2b+1)a-1][(b-1)a-b]
=(2ab+a-1)(ab-a-b)