Это вставляешь в кубик C#
double[] xVal = new double[]{0, 1, 2};
double[] yVal = new double[]{20, 22, 24};
double rsquared;
double yintercept;
double slope;
CommonCode.LinearRegression(xVal, yVal, 0, xVal.Length, out rsquared, out yintercept, out slope);
//return yintercept.ToString()...