Suppose you have to factor a polynomial like *x*^{2}
− 5*x* + 6. That is, there's nothing in front of
the *x*^{2}, but there can be a linear term and a
constant term. You need to find two numbers whose sum is 6 (the
constant term) and whose product is −5 (the number in front
of the *x*). The numbers that work are −2 and −3.
(It doesn't matter what order we put them in.) Then the two
factors are *x* − 2 and *x* − 3, so the
answer is (*x* − 2)(*x* − 3).

- If there's no number in front of the
*x*, then it's just as if there was a 1 there (or a −1, if it was −*x*). - If there's no constant term, then it's as if the constant term is 0.
- Finally, if there's no
*x*(just an*x*^{2}), then it's as if there a 0 in front of the*x*.