Factorise

3px-3py-x+y

note that the fits two terms are

3p(x-y)

and then use grouping.

To factorize the expression 3px - 3py - x + y, we need to look for common factors.

Step 1: Group the terms with common factors together.
(3px - x) - (3py - y)

Step 2: Factor out the common factor from each group.
x(3p - 1) - y(3p - 1)

Step 3: Notice that both groups have a common factor of (3p - 1).

Therefore, the factorization of the expression 3px - 3py - x + y is:
(3p - 1)(x - y)