/// <summary>
 /// Performs subtraction operation of two polynomials.
 /// </summary>
 /// <param name="minuend">Minuend</param>
 /// <param name="subtrahend">Subtrahend</param>
 /// <returns>Difference</returns>
 /// /// <exception cref="ArgumentNullException"><paramref name="first"/> is null.</exception>
 /// <exception cref="ArgumentNullException"><paramref name="second"/> is null.</exception>
 public static Polynomial Subtract(Polynomial minuend, Polynomial subtrahend)
 {
     return(minuend - subtrahend);
 }
 /// <summary>
 /// Performs addition operation of two polynomials.
 /// </summary>
 /// <param name="first">Augend</param>
 /// <param name="second">Addend</param>
 /// <returns>Sum</returns>
 /// /// <exception cref="ArgumentNullException"><paramref name="first"/> is null.</exception>
 /// <exception cref="ArgumentNullException"><paramref name="second"/> is null.</exception>
 public static Polynomial Add(Polynomial first, Polynomial second)
 {
     return(first + second);
 }