Which have some important facts:
(i) , i.e., the two complex roots of the equation are conjugate of each other.
(ii) , i.e., the square root of any one complex roots is the other complex root.
(iii) If we denote to be one complex root, then the three roots are .
(iv) Since is a root of equation , we obtain , where , , i.e., , .
(v) , i.e, the sum of the three cube roots of unity vanishes.