using System;

public class Program

{

    public static void Main()

    {

        int a = 1;

        int b = 8;

        int c = -9;

        double delta = (b * b) - (4 * a * c);

        double raiz = Math.Sqrt(delta);

        var x1 = ((-(b)) + raiz) / (2 * a);

        var x2 = ((-(b)) - raiz) / (2 * a);

        Console.WriteLine("Valor de X': {0}", x1);

        Console.WriteLine("Valor de X'': {0}", x2);

    }

}