Suppose that R(x) is a polynomial of degree 8 whose coefficients are real numbers. (Complex zeros)

Suppose that R(x) is a polynomial of degree 8 whose coefficients are real numbers, Also, suppose that R(x) has the following zeros: 2, 2-4i, - i.
Find another zero of R(x) and determine the maximum number of real zeros that R(x) can have.