C#求解一元二次方程

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
//求解一元二次方程ax^2+bx+c=0;
namespace 平时练习
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("输入a,b,a的值：");
            string a = Console.ReadLine();
            string b = Console.ReadLine();
            string c = Console.ReadLine();
            Console.WriteLine(a+"x^2+"+b+"x+"+c+"=0");
            double a1 = double.Parse(a);
            double b1 = double.Parse(b);
            double c1 = double.Parse(c);
            Judge(a1,b1,c1);
        }

        private static void Judge(double a1, double b1, double c1)
        {
            double result = b1 * b1 - 4 * a1 * c1;
            double d = Math.Sqrt(result);
            double m = 2 * a1;
            double xs = -b1 / m;
           
            if (result < 0)
                Console.WriteLine("无解。");
            else if (result == 0)
            {
                Console.WriteLine("有一个解：{0}", xs);
            }else 
            {
                double x1 = xs + d / m;
                double x2 = xs - d / m;
                Console.WriteLine("有2个解x1={0},x2={1}",x1,x2);
            }
        }
    }
}