public static void Main()
Console.WriteLine("Chao ban da toi phan mem tinh nghiem Phuong Trinh Bac 2");
Console.WriteLine("Moi ban nhap so a");
int a = int.Parse(Console.ReadLine());
Console.WriteLine("Moi ban nhap so b");
int b = int.Parse(Console.ReadLine());
Console.WriteLine("Moi ban nhap so C");
int c = int.Parse(Console.ReadLine());
Console.WriteLine($"Phuong trinh bac 2 nhu sau: {a}*x^2 + {b}*x + {c} = 0");
double delta = b * b - 4 * a * c;
double x1 = (-b + Math.Sqrt(delta)) / (2 * a);
double x2 = (-b - Math.Sqrt(delta)) / (2 * a);
Console.WriteLine($"Nghiem thu nhat cua phuong trinh bac 2 la: {x1}");
Console.WriteLine($"Nghiem thu hai cua phuong trinh bac 2 la: {x2}");
Console.WriteLine($"Phuong trinh co nghiem kep {x}");
Console.WriteLine("Phuong trinh vo nghiem");