Explanation:
In mathematics, factorization (also factorisation in British English) or factoring is the decomposition of an
object (for example, a number, a polynomial, or a matrix) into a product of other objects, or factors, which when multiplied together give the original. For example, the number 15
factors into primes as 3 × 5, and the polynomial x2 − 4 factors as (x − 2)(x + 2). In all cases, a product
of simpler objects is obtained.
The aim of
factoring is usually to reduce something to "basic building blocks,"
such as numbers to prime numbers, or polynomials to irreducible polynomials.
Sum/difference of two squares
Another common type of algebraic factoring is called the difference of two squares. It is the application of the formula

to any two terms, whether or not they are perfect squares. If
the two terms are subtracted, simply apply the formula. (Our solved example in mathguru.com
uses this concept)
http://en.wikipedia.org/wiki/Factorization
The above explanation is copied from
Wikipedia, the free encyclopedia and is remixed as allowed under the Creative
Commons Attribution- ShareAlike 3.0 Unported License.