[tex]\qquad \textit{power of two complex numbers} \\\\\ [\quad r[cos(\theta)+isin(\theta)]\quad ]^n\implies r^n[cos(n\cdot \theta)+isin(n\cdot \theta)] \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ z=3[\cos(30^o)+i\sin(30^o)] \\\\\\ z^3=3^3[\cos(3[30^o])+i\sin(3[30^o])]\implies z^3=27[\cos(90^o)+i\sin(90^o)] \\\\\\ z^3=27(0~~ + ~~i1)\implies z^3=0+27i[/tex]
so that gives us the point (0 , 27) on the imaginary plane, and we also know the line goes through the origin, since it'd be a line in component form, and to get the equation of a line we only need two points off of it, let's use those two.
[tex]\stackrel{origin}{(\stackrel{x_1}{0}~,~\stackrel{y_1}{0})}\qquad (\stackrel{x_2}{0}~,~\stackrel{y_2}{27}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{27}-\stackrel{y1}{0}}}{\underset{run} {\underset{x_2}{0}-\underset{x_1}{0}}}\implies \cfrac{27}{0}\implies und efined[/tex]
a line with an undefined slope is a vertical line, namely in this case x = 27.