A difference of squares is square number (a number multiplied
by itself) subtracted from another square number.
A Real Example of a Difference of Squares
It is easier to understand a difference of squares with an example.
In this example,
32 = 3 × 3 = 9 (3 squared).
22 = 2 × 2 = 4 (2 squared).
The two numbers are square numbers
. They are squares
Two numbers are being subtracted
from each other. It is a difference
A Difference of Squares in General
In general, we can use symbols instead of numbers:
are both integers
How to Factor a Difference of Squares
A difference of squares can be factored into two brackets:
The slider below shows why a difference of squares can be factored as a2 − b2 = (a + b)(a − b).