# Understanding this for factoring

• Apr 25th 2012, 08:38 AM
Kibbygirl
Understanding this for factoring
Factor completly:
(3n-1)2 - (3n-1) - 72

What do you use to process this? If there is nothing to work with the -72? You can factor out (3n-1) correct? But still left with the -72?
• Apr 25th 2012, 08:44 AM
Plato
Re: Understanding this for factoring
Quote:

Originally Posted by Kibbygirl
Factor completly:
(3n-1)2 - (3n-1) - 72

$x^2-x-72=(x-9)(x+8)$. Let $x=3n-1.$