Factoring a Difference of Squares

Consider (a + b)(a - b)    =    a²     -    b².                     

The binomial given above is called a difference of squares. since it is of the form
a square minus a square.  To factor a difference of squares 

 Take a square root of the first term, a²  of the binomial. 
 Take a square root of b². 
 Add the two square roots together to obtain one of the factors. 
 Take the difference of the two square roots to obtain the other factor.

Sq rt a                Sq rt b 
   a²        -       b²     =         (a + b)(a - b)

Example:

Sq rt 2x               Sq rt 3y 
  4x²        -       9y²     =         (2x + 3y)(2x - 3y)

Go back to previous page.

Go back to home page.

Copyright © 1995 - Present.  SSmyrl