How do I factorize (further) this? I do not understand the steps, I know the answer although.
The question goes:
1)
(x-b)^2-x+b
=(x-b)^2-(x-b)
=(x-b)(x-b-1)
I do not understand the steps from 2nd to 3rd.
2)
x^2-y^2-(x-y)^2
=(x-y)(x+y)-(x-y)^2
=(x-y)[x+y-(x-y)]
=(x-y)(x+y-x+y)
=(x-y)(2y)
=2y(x-y)
I do not get the step from 1 to 2.
Explanation would be appreciated.