C#Basics HW4 Problem6 - advanced2

using System;
class QuadraticEquation
{
static void Main()
    {
        Console.WriteLine("This program solves quadratic equations of the form ax^2 + bx + c = 0");
        Console.Write("Please enter coefficient a: ");
        double a = double.Parse(Console.ReadLine());
        Console.Write("Please enter coefficient b: ");
        double b = double.Parse(Console.ReadLine());
        Console.Write("Please enter coefficient c: ");
        double c = double.Parse(Console.ReadLine());
        double discriminant = b * b - 4 * a * c;     //calculations start here
        if (discriminant < 0)
        {
            double x1 = -b / 2 / a;
            double complexPartOfDiscriminant = Math.Sqrt(-discriminant)/2;
            System.Console.WriteLine("The solution of the equation is : x1 = {0} - {1}i, x2 = {0} + {1}i", x1,                      complexPartOfDiscriminant);
        }
        else if (discriminant == 0)
        {
            double x = - b / 2 / a;
            Console.WriteLine("Double root x1 = x2 = {0}",x);
        }
        else
        {
            double x1 = ( - b - Math.Sqrt(discriminant)) / 2 / a; // Weird, usually the first root is with + in the formula
            double x2 = ( - b + Math.Sqrt(discriminant)) / 2 / a; // I guess they want to test our attentiveness :)
            Console.WriteLine("The solution of the equation is : x1 = {0}, x2 = {1}", x1, x2);
        }
    }
}