Factoring ax2 + bx + c
Step 1:- Find pairs whose product is a. Write all pairs of integer factors
of the coefficient of the squared term, a.
Step 2 :- Find pairs whose product is c. Write all pairs of integer factors
of the last term, c.
Step 3 :- Choose inner and outer terms. Use FOIL and various combinations
of the factors from Steps 1 and 2 until the necessary
middle term is found.
If no such combinations exist, the trinomial is prime.