Answer
The missing zeros of the given function are $\color{blue}{\bf-i \text{ and }-2i}$.
Work Step by Step
RECALL:
If $a+bi$ is a zero of a polynomial function with real number coefficients, then its conjugate $a-bi$ is also a zero of the function.
Thus, the missing zeros of the given function are the conjugates of $i$ and $2i$, which are: $\color{blue}{\bf-i, -2i}$