I can't seem to figure out how to check this problem.

8x^3 + 1 =0

I factored it and got

(2x+1)(4x^2 - 2x + 1)

So x=-1/2 and x= (1±i sqrt 3)/4

The first solution -1/2 seems to satisfy the equation, but I can't figure out how to check for the second solution.

8[(1±i sqrt 3)/4]^3 +1=0

I multiplied the first two numbers and got

(-2±i sqrt 3)/2 + 1

and then I got stuck...

So, could someone please tell me where to go from here?

Any help would be greatly appreciated.

Thanks