1. Factoring – Difference of Two Squares
a.k.a “DOTS”
Make sure you always check for a GCF first!
If you skip right to DOTS when there is a GCF, you will probably get the question wrong.
After checking for a GCF, make sure the following are true:
Are there only 2 terms?
Is there a minus sign between the two terms (difference)
Are both terms perfect squares?
If all of these answers are yes, then it is time for DOTS

2. Factoring – Difference of Two Squares
How to factor a Polynomial Using DOTS:
Check for a GCF
Make sure it is in fact DOTS
Set up 2 ( )
Take the square root of each term, place in corresponding part of each ( )
If you want, you can multiply (Double Distribute/FOIL) to check your answer
x2 – 16

3. Factoring – Difference of Two Squares
Practice Examples:
y2 – 9
4b2 – 25
25a2 – 16
36m2 – 49p2
x2 + 25 4x