what is x cubed in exponential

what is x cubed in exponential form

$$\small{\text{$ \begin{array}{rcl} x^3 &=& e^z \qquad | \qquad \ln{()}\\ \ln{(x^3)} &=& \ln{(e^z)}\\ 3\ln{(x)} &=& z\ln{(e)}\qquad | \qquad \ln{(e)}=1\\ 3\ln{(x)} &=& z\\\\ \mathbf{x^3} & \mathbf{=} & \mathbf{e^{3\ln{(x)}}}\\ \\ \hline \\ \end{array} $}}$$