# Thread: What are a, b and c?

1. ## What are a, b and c?

Hi,

This has complex numbers in

I have the equation $z^3 + az^2 + bz + c = 0$ where the solutions for z= -2-i, -2+i and 2.

How do I go about finding a, b and c?

I've tried subbing back into the equation but it ends up getting far too complicated

2. (z-2)(z+2-i)(z+2+i)=0
(z-2)((z+2)^2-i^2)=0
z^3+2z^2-3z-10=0