The difference of two squares factoring pattern states that a difference of two squares can be factored as follows:
So, whenever you recognize the two terms of a subtraction to be two squares, you can factor it as the sum of the roots multiplied by the difference of the roots.
In this case, the squares are obvious: is the square of
, and
is the square of
So, we can factor the expression as
(the round parenthesis aren't necessary, I used them only to make clear the two terms)
We can simplify the expression summing like terms: