use the given zero to find the remaining zeros of the function:

F9x)=x^3-5x^2+4x-20; zero:2i

I don't get it. Can someone please show me what to do with this?

if 2i is a zero, so is -2i

so, (x-2i)(x+2i) = x^2+4 divides f(x)
doing the division, we have
f(x) = (x-5)(x^2+4)
so, the zeros are 5,2i,-2i