# Math Help - Factoring Help - hw due help!

1. ## Factoring Help - hw due help!

Math HW due.. need help tonight bad.

Need to factor the following
(If I erase some of the problems, its because someone already did them. thanks)

2. 27x^3-64

3. 3x^3+x^2-12x-4

2. $27x^3 - 64$ is a difference of two cubes - consider it written as $(3x)^3 - 4^3$. Use the formula for difference of two cubes with $a=3x$ and $b=4$.

For the other problem, $3x^3+x^2-12x-4$, out of the first two terms, factor $x^2$ and out of the last two terms factor out -4. This gives:

$x^2(3x+1)-4(3x+1)$. Now, both terms have a $(3x+1)$ in common, so factor that out, giving:

$(3x+1)(x^2-4)$. The last step for finishing this one is to factpr $x^2-4$, which is a difference of squares.

Hope this helps!