1
er Ejercicio resuelto en C#: 
Quadratic Equation
Description
Write a program that reads the coefficients a, b and c of a quadratic equation ax2 + bx + c = 0 and solves it (prints its real roots).
El código:
using System;
namespace QuadraticEquation {
	class Program {
		static void Main() {
			double a = double.Parse(Console.ReadLine());
			double b = double.Parse(Console.ReadLine());
			double c = double.Parse(Console.ReadLine());
			double raizPositiva = (-b+(Math.Sqrt(Math.Pow(b,2)-4*a*c)))/(2*a);
			double raizNegativa = (-b-(Math.Sqrt(Math.Pow(b,2)-4*a*c)))/(2*a);
			if(raizNegativa.ToString() == "NaN" || raizPositiva.ToString() == "NaN") {
				Console.WriteLine("no real roots");
			}else if(raizPositiva != raizNegativa) {
				Console.WriteLine("{0:0.00}",raizNegativa);
				Console.WriteLine("{0:0.00}",raizPositiva);
			}else {
				Console.WriteLine("{0:0.00}",raizPositiva);
			}
			
		}
	}
}
Saludos.