Algebra

9x^2  - 4

We have a difference of squares.....so......

a^2 - b^2 =  (a + b) (a - b)

Let   a^2  = 9x^2   so....a = 3x

Let b^2 = 4  so......b = 2

So we have

9x^2 - 4  =   (3x + 2) (3x - 2)

We see a difference of squares! \(\sqrt9=3, \sqrt4=2\) so...

\((3x+2)(3x-2)\).

You are very welcome!

:P