Principal root of the third root of 8

Question

I feel like I am right on this question but I keep getting it wrong. I have tried inputting 2 and $2+0i$. Am I missing something?

Thank you.

Answer 1

Thank you everyone for the ideas and help. The program wanted it like this... $2, -1+i\sqrt{3}, -1-i\sqrt{3}$. I feel like the instructions should be improved personally.