Answer
$x=\pm 216$
Work Step by Step
$6x^{2/3}-216=0$
We add 216:
$6x^{2/3}=216$
And divide by 6:
$x^{2/3}=36$
And solve for $x$, paying attention to the possible signs of the solution:
$(x^{2/3})^{3/2}=[36]^{3/2}=[(\pm 6)^{2}]^{3/2}$
$x=(\pm 6)^{3}=\pm 216$
