# Factoring a Difference of Squares – Practice Problems

When an expression can be viewed as the difference of two perfect squares, i.e. a²-b², then we can factor it as (a+b)(a-b).

For example:

x²-36 is equal to (x-6)(x+6).

Check this by using the FOIL method or by distributing twice:

x² – 6x + 6x – 36 = x² -36

Another example:

4x^{2} – 16 is equal to (2x – 4)(2x + 4)

Check this by using the FOIL method or by distributing twice:

4x² – 8x + 8x – 16 = 4x² – 16