double? result
double denominator = 0;
double Numerator = 100;
result = Numerator / NullIf(denominator, 0);
result = Numerator / denominator.NullIf(0);
result = Numerator / Object.NullIf(denominator, 0);

result = Numerator / (denominator == 0 ? (double?)null : denomiantor);

Nullable<T> NullIf<T>(T left, T right)
{
    return left == right ? (T?)null : left;
}

result = Numerator / NullIf(denominator, 0);

public static Nullable<T> NullIf<T>(T first, T second) where T : struct
{
    if(first == second)
        return new Nullable<T>();
    return new Nullable<T>(first);
}

double? result
double denominator = 0;
double Numerator = 100;
result = denominator == 0 ? (double?)null : Numerator / denominator;

result = x ?? 0;

result = x.HasValue? x.Value : 0;

public static T? NullIf<T>(T left, T right) where T : struct
{
    return EqualityComparer<T>.Default.Equals(left, right) ? (T?)null : left;
}

public static T? NullIf<T>(this T value, Func<T,bool> isConsideredNull)
{
        if(value == null)
        {
           return null;
        }
        return isConsideredNull(value) ? (T?)null : value;
}

string test = "NULL";

test.NullIf((x)=> x.Equals("NULL"));
test.NullIf((x)=> x == "NULL");
test.NullIf((x)=> x.Equals("NULL",StringComparison.InvariantCultureIgnoreCase));

public static bool AnyNull<T>(this IEnumerable<T> values) where T : class
        {
            if (values == null)
            {
                throw new ArgumentNullException(nameof(values));
            }
            return values.Any(obj => obj == null);
        }