The masses $ m_i $ are located at the points $ P_i $. Find the moments $ M_x $ and $ M_y $ and the center of mass of the system.

$ m_1 = 5 $ , $ m_2 = 4 $ , $ m_3 = 3 $ , $ m_4 = 6 $ ;

$ P_1 (-4, 2) $ , $ P_2 (0, 5) $ , $ P_3 (3, 2) $ , $ P_4 (1, -2) $