public static void SolutionReal(Quadratic eq)
 {
     if (eq.Discriminant < 0)
     {
         return;
     }
     Console.WriteLine(eq.ToString() + "  дискриминант = " + eq.Discriminant);
     Console.WriteLine("\tКорни: Х1={0,3:g3}  \tX2={1,3:g3}", eq.X1, eq.X2);
 }
 public static void PrintEq(Quadratic eq)
 {
     Console.WriteLine(eq.ToString() + "  дискриминант = " + (eq.Discriminant).ToString("g3"));
 }