8 In this question you must show detailed reasoning.
You are given that i is a root of the equation \(z ^ { 4 } - 2 z ^ { 3 } + 3 z ^ { 2 } + a z + b = 0\), where \(a\) and \(b\) are real constants.
- Show that \(a = - 2\) and \(b = 2\).
- Find the other roots of this equation.