# factoring basic college algebra problem

• September 22nd 2010, 04:42 PM
siberianfog
factoring basic college algebra problem
cant figure this one out. just need to factor it
8r^3 - 27

ive got to

(2r)^3 - 3^3
• September 22nd 2010, 05:12 PM
skeeter
Quote:

Originally Posted by siberianfog
cant figure this one out. just need to factor it
8r^3 - 27

ive got to

(2r)^3 - 3^3

the factoring format for the difference (and sum) of two cubes should be in your text ...

$a^3 - b^3 = (a-b)(a^2+ab+b^2)$