factoring a trinomial
1. Write the trinomial in descending order of powers of the variable being used.
2. Factor out the GCF. If the first term is negative, factor out a as well.
3. Check to see if the trinomial is now factorable.
4. If it is not yet factorable, manipulate the trinomial to take the form of a factorable trinomial, then factor.
5. Check that the factorization is valid by multiplying the binomials to result in the original trinomial.