Find the greatest common factor first
Group terms if there are four or more terms
Use special identities such as a^2 – b^2 = (a – b)(a + b)
Use special identities such as a^2 + 2ab + b^2 = (a + b)^2
Use special identities such as a^2 – 2ab + b^2 = (a – b)^2
Split the middle term in quadratic expressions
Find two numbers whose product and sum match the quadratic
Rewrite the expression using those numbers
Factor by grouping
Check by multiplying the factors back together