Editing Difference of two squares (section)

{{short description|Mathematical identity of polynomials}}
In [[elementary algebra]], a '''difference of two squares''' is one [[square (algebra)|squared]] number (the number multiplied by itself) [[subtraction|subtracted]] from another squared number. Every difference of squares may be [[Factorization|factored]] as the [[Multiplication|product]] of the [[addition|sum]] of the two numbers and the [[Subtraction|difference]] of the two numbers:

<math display=block>a^2-b^2 = (a+b)(a-b).</math>

In the reverse direction, the product of any two numbers can be expressed as the difference between the square of their [[arithmetic mean|average]] and the square of half their difference:

<math display=block>xy = \left(\frac{x + y}{2}\right)^2 - \left(\frac{x - y}{2}\right)^2.</math>