How To Find Zeros Of Cubic Polynomial If One Zero Is Given. The table below summarizes the four cases for the zeros of a cubic and how many roots are real or complex. Any polynomial in x with these zeros will be a multiple (scalar or polynomial) of this f (x).

Now equating the function with zero we get, 2x+1=0. If one of the zeros of the cubic polynomial. P = − 1 4 ( 1 − i 3) 1 2 ( 1 + i 3) 3 − 1 2 ( 1 2 ( 1 + i 3)) 2 / 3.