well, ok, the x intercepts aer where the function equals 0 also if the x intercepts are r1 and r2 then the factored form of the function is f(x)=a(x-r1)(x-r2) where a is a constant well, we have it already in that form
f(x)=(x-3i)(x-3i) the x intercept is at x=3i standard form requires expansion we expand to get f(x)=x²-6i-9