# Math Help - factorizing

1. ## factorizing

factorizing this:

$
x^4-64x
$

$
= (x^2+8)(x+4)(x-4)
$

correct?

2. I don't think so. Pull out an x immediately. $x(x^3-64)$. Now write 64 as a cube. $x(x^3-4^3)$. Now you can plug this into a difference of cubes formula.

When you expand the answer you have back out, it doesn't give the original expression.

3. Originally Posted by Jameson
I don't think so. Pull out an x immediately. $x(x^3-64)$. Now write 64 as a cube. $x(x^3-4^3)$. Now you can plug this into a difference of cubes formula.

When you expand the answer you have back out, it doesn't give the original expression.
ahhh yeah so

$x(x^3-4^3)$
$x(x-4)(x^2+4x+16)$

?

4. You got it