Question 958161
I'm assuming n is the degree of the polynomial you're seeking(?).
{{{y=(x-i)(x-2i)(x-a)}}}
where {{{a}}} is an unknown to solve.
{{{-30=(-1-i)(-1-2i)(-1-a)}}}
{{{-30=(1+2i+i+2i^2)(-1-a)}}}
{{{-30=(-1+3i)(-1-a)}}}
{{{-1-a=-30/(-1+3i)}}}
{{{-1-a=(-30/(-1+3i))((-1-3i)/(-1-3i))}}}
{{{-1-a=(30+90i)/(1+3i-3i-9i^2)}}}
{{{-1-a=(30+90i)/(1+9)}}}
{{{-1-a=(30+90i)/10}}}
{{{-1-a=3+9i}}}
{{{a=-4-9i}}}
So then,
{{{y=(x-i)(x-2i)(x-(-4-9i))}}}
{{{highlight(y=(x-i)(x-2i)(x+4+9i))}}}