The Fundamental Theorem of Algebra (FTAL) states that if f(x) is a polynomial of degree n, where n is a positive integer, then f has at least one zero in the complex number system, and f(x) can be written of n linear factor with complex coefficients.
Notice that the solution set to f(x) = 0 must be found, if one needs to find factorization of f (x) over the Complex number system as mandated by FTAL.