public static void Main()
double a, b, c, x, denta, x1, x2;
Console.WriteLine("Nhap a");
a=double.Parse(Console.ReadLine());
Console.WriteLine("Nhap b");
b=double.Parse(Console.ReadLine());
Console.WriteLine("Nhap c");
c=double.Parse(Console.ReadLine());
Console.WriteLine("PTVSN");
Console.WriteLine("PTVN");
Console.WriteLine("Nghiem la x ="+ x);
Console.WriteLine("Phuong trinh vo nghiem");
Console.WriteLine("Phuong trinh co nghiem kep x1=x2= "+x1);
x1=(-b+Math.Sqrt(denta))/(2*a);
x2=(-b-Math.Sqrt(denta))/(2*a);
Console.WriteLine("Phuong trinh co 2 nghiem phan biet x1="+x1+"va x2="+x2);