For the polynomial function:
f(x) = 4x^10 + 20x^9 + 35x^8 + 127x^7 + 35x^6 - 533x^5 + 433x^4 - 487x^3 + 321x^2 + 153x -108,
a) Employ techniques (possibly synthetic division) to find out all the zeros of the polynomial. (Hint: i is a zero).
b) Write the function in factored form, including any complex factors.