public static void Main()
Console.WriteLine("ax² < b");
Console.Write("a = "); int a = int.Parse(Console.ReadLine());
Console.Write("b = "); int b = int.Parse(Console.ReadLine());
if (a != 1 && a != -1) Console.WriteLine("\n{0}x² < {1}", a, b);
if (a == 1) Console.WriteLine("\nx² < {0}", b);
if (a == -1) Console.WriteLine("\n-x² < {0}", b);
x = Math.Sqrt(Math.Abs(b/(double)a));
if (b <= 0) Console.WriteLine("No Solution");
else Console.WriteLine("Solution: x ∈ (-{0:f2}; {0:f2})", x);
if (b < 0) Console.WriteLine("Solution: x ∈ (-inf; -{0:f2}) U ({0:f2}; +inf)",x);
if (b >= 0) Console.WriteLine("Solution: x ∈ ℝ");
if (b > 0) Console.WriteLine("Solution: x ∈ ℝ");
else Console.WriteLine("No Solution");