Write the trinomial in standard form: ax² + bx + c
Find two numbers that multiply to a × c and add to b
Rewrite the middle term using those two numbers
Group the four terms into two pairs
Factor out the greatest common factor from each pair
Factor out the common binomial
Check by multiplying the factors back together
If a = 1, find two numbers that multiply to c and add to b
If a ≠ 1, use the AC method
If the trinomial is a perfect square, factor it as a binomial squared
If no integer pair works, the trinomial may be prime over the integers