Question 274624
If it has a zero of 2i it has to have a zero of -2i.
(x+3)(x-3)(x+2i)(x-2i)
=(x^2-9)(x^2-4i^2)
=(x^2-9)(x^2+4) (i^2=-1)
=x^4-5x^2-36
.
Ed