Factorize each of the following expression:

$256 x^{5}-81 x$

$=x\left(256 x^{4}-81\right)$

$=x\left[\left(16 x^{2}\right)^{2}-9^{2}\right]$

$=x\left(16 x^{2}+9\right)\left(16 x^{2}-9\right)$

$=x\left(16 x^{2}+9\right)\left[(4 x)^{2}-3^{2}\right]$

$=x\left(16 x^{2}+9\right)(4 x+3)(4 x-3)$