Answer
$z^{36}$
Work Step by Step
We are given the expression $(z^{4})^{9}$.
To simplify, we can use the power rule, which holds that $(a^{m})^{n}=a^{m\times n}$ (where a is a real number, and m and n are integers).
$(z^{4})^{9}=z^{4\times9}=z^{36}$