Zeros: -1, 2, -3i
Write the equation of the polynomial function
(x + 1)(x - 2)(x + 3i)
= x^3 - 3x^2 - 2x + 3i(x^2 - 3x - 2)
Since -1 is a zero, you know that (x+1) is one of the factors of the polynomial.
Likewise, (x-2) and (x+3i) are also factors.
Multiply the factors to get the polynomial. So (x+1)(x-2)(x+3i) = the polynomial. Just multiply, and combine like terms.