Factor completely the polynomial. 7a–7b+an–bn

The answer is (a - b)(7 + n)

Looking at the polynomial, you will notice that there are two terms with a 7, two terms with an "a", two terms with a "b", and two terms with an "n". We can get such a polynomial from using FOIL.

FOIL is when we multiply two binomials together by multiplying the first terms together, the outer terms together, the inner terms together, and the last terms together.

Notice that "a" and "b" do not share a term. Likewise, 7 and "n" do not share a term. Therefore, these two pairs go together to form our binomials. To figure out what signs to use, play around with the terms until you get the  right answer. In this case we can assume that the b is negative because both terms in the given polynomial that have b are negative.