## Elementary Geometry for College Students (7th Edition)

$x^3-9x = (x)~(x+3)~(x-3)$
The general form of factoring the difference of two squares is as follows: $x^2-y^2 = (x+y)~(x-y)$ Let's consider this trinomial: $~x^3-9x$ First we can factor by using the GCF: $x^3-9x = (x)~(x^2-9)$ Then we can factor by using the difference of two squares. We can factor the trinomial as follows: $x^3-9x = (x)~(x^2-9)$ $x^3-9x = (x)~(x+3)~(x-3)$