# Factoring sum of two cube

• January 28th 2010, 07:08 PM
Anemori
Factoring sum of two cube

factor sum of two cube:
27x+3x^3

can you explain me by steps? thank you!
• January 28th 2010, 07:35 PM
Quote:

Originally Posted by Anemori

factor sum of two cube:
27x+3x^3

can you explain me by steps? thank you!

$27x+3x^3$

This isn't the sum of two cubes. Although 27 is a cube, $27x$ is not a cube. Also, $3x^3$ isn't a cube either.

You can factor out $3x$ to obtain:

$x(27+3x^2)=3x(9+x^2)$
• January 29th 2010, 03:33 AM
integral
$(a^3+b^3)=(a+b)(a^2-ab+b^2)$

But this will not work for your expression as said above.