How to factorise this expression $ x^2-y^2-x+y$ This part can be factorised as  $x^2-y^2=(x+y)(x-y)$, How would the rest of the expression be factorised ?
:)

Notice here,
$$x^2 - y^2 - x + y$$
$$(x+y)(x-y)-1(x-y)$$
$$(x-y) (x+y-1)$$
That's done.
