and

$\displaystyle 2sin^3(3x) - sin^2(3x) - 2sin(3x) +1 = 0$

I got down half of it $\displaystyle 3x = arcsin(1/2)$

The other half is what is confusing me. How do I get the values for x on this one? $\displaystyle 3x = arcsin(+/- sqrt(1))$

I know arcsin is opposite / hypotenuse.