Difference of Squares

A difference of squares is where you have a variable, that has a even power (2,4,6,8,etc.) and is having a perfect square being subtracted from it. The typical from loks like this. AX²-B, where A and B are perfect squares and can be square rooted.
So for example, the figure X²-4 is a Difference of squares. So you factor it by square rooting each term
√X² - √4 gives you X-2 right? But there is a rule, that if you take an eventh root from an eventh power, yeilding an odd power, you must also give its conjugate as another solution, and the conjugate to X-2 is X+2. So this is why you have the difference of squares.