What is the correct value? My confusion is:
$(-9)^{2/3} = ((-9)^{2})^{1/3} = ((-9)^{(1/3)})^{2} = 4.32$
But my calculator shows math error, and google says:
$(-9)^{2/3} = 2.16+3.74i$ 

It is because it is showing one of the three possible roots, one of them being $4.32$, and the other two are $2.16 + 3.74i$ and its conjugate
