C# - Lineare Funktion aus 2 Punkten erzeugen

public static string getFunction1(double p1x, double p1y, double p2x, double p2y)
        {
            double store = p2x-p1x;
            double m = (p2y - p1y) / store;
            double n = p1y - (m * p1x);
            if (n == 0)
                return "f(x):" + m + "x";
            else if (n > 0)
                return "f(x):" + m + "x+" + n;
            else
                return "f(x):" + m + "x" + n;
        }