I've got an expression like
expr = (1-x)(a+b)
that I would like to distribute / expand while keeping factors of
(1-x) intact, i.e. the result should in the above example should look like
(1-x)a + (1-x)b
I know that for the explicit example given here,
Expand[expr,(a+b)] would yield the desired result. However, I would need a solution where
(a+b) can be any arbitrary algebraic expressions that is distributed with
(1-x) being left untouched.
Is there maybe a way to define a pattern that matches my
(1-x) terms that I can than hold while distributing?