import numpy as np

X = np.array([[1,2,3],[1,3,6]])

y = np.array([[5,6]]).T

X_m = np.matrix(X)

y_m = np.matrix(y)

# fi = (X.T * X)**-1 * X.T * y

fi = (X_m.T * X_m)**-1 * X_m.T * y_m

print('\nWynik działania (X.T * X)**-1 * X.T * y to:\n')
print(fi)