1-x^6 shows that it has 6 answers.
2-the complex conjugate root theorem states that if P is a polynomial in one variable with real coefficients, and a + bi is a root of P with a and b real numbers, then its complex conjugate a − bi is also a root of P.
so conjugate of root √6-1 is √6+1 . for -2 -√2 is -2+√2 and for -3-i is -3+i.