TIPS FOR FACTORING ax2 + bx + c, a ≠ 1
a. Always factor out the largest common factor, if one exists.
b. Once the common factor has been factored out of the original
trinomial, no binomial factor can contain a common factor
(other than 1 or _1).
c. If c is positive, then the signs in both binomial factors must
match the sign of b. (This assumes that a > 0. )
d. Reversing the signs in the binomials reverses the sign of the
middle term of their product.
e. Organize your work so that you can keep track of which
possibilities have or have not been checked.
f. Always check by multiplying.