ANSWER
[tex] 256 {x}^{4} [/tex]
EXPLANATION
The given expression is
[tex] {(4x)}^{4} [/tex]
Recall that,
[tex] {(ab)}^{m}={(a}^{m}{b}^{m})[/tex]
We apply this property to get,
[tex] = ( {4}^{4} {x}^{4} )[/tex]
This simplifies to,
[tex] = 256 {x}^{4} [/tex]
