My stupid math teacher...

[gaelic cowboy]

This has to be a mistake teacher probably meant to write X^2 not X^3 unless you left some of the question out???

answer is X^2=6 for me anyway and if they are really looking for X^3 then the answer is 6 x (sqrroot6)

But my money is on a simple mistake in writing the question and that it is supposed to be X^2