In mathematics, a cube root of a number x is a number a such that a = x. All real numbers (except zero) have exactly one real cube root and a pair of complex conjugate cube roots, and all nonzero complex numbers have three distinct complex cube roots. For example, the real cube root of 8, denoted √8, is 2, because 2 = 8, while the other cube roots of 8 are −1 + √3i and −1 − √3i. The three cube roots of −27i are