.
Such function has the root of 
, which is conjugate to 
over the field of rational numbers, and the root 1-i, conjugate to 1+i 
over the field of real numbers.
So, the full list of the roots consists of 5 numbers {0, 
, 
, 1+i, 1-i}.
Thus your polynomial is
    p(x) = 
 = 
         = 
 = 
 = 
.
You can transform it to any other equivalent form.
Solved.