Week 10 – Difference of squares

This week in math we looked over the difference of squares, a a concept we discovered in week 9 where you use the method as a way of skipping the distributive method while evaluating your expression.

The method works as follows:

(a+b) (a-b)

= $a^2$ + ab – ba – $b^2$

= $a^2$$b^2$

This can be used to work backwards as well, when factoring expressions.

Example:

75$x^2$$y^2$ -3

First we remove the common factor,

3 (25$x^2$$y^2$ -1)

Then we factor.

3 (5xy – 1) (5xy + 1)