How to factor : (x-y)+(x-y)(x+y)

I have no idea where to start, please help. I know the answer, I just need to know the steps/the process.

x - y is a common factor of both x - y and (x - y)(x + y), so factor it out to get:
(x - y) + (x - y)(x + y) = (x - y)(1 + x + y).

Note that you can technically write x - y as 1(x - y), so when you pull out x - y, you are left with just 1.

I hope this helps!

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

a + ab

a(1 + b)

( x - y ) [ 1 + ( x + y ) ]

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