The emphasis of the article is a potential usage of Jordan - Gauss successive elimination method for reduction of a differential equation system (DES) to one differential equation and determining its solution providing all other solutions of DES. This approach is different from standard method of determining of eigen vectors and eigen values of matrix of DES, which are necessary to determine fundamental system of solutions of homogeneous differential equations of n-th order with constant coefficients denoted in norm form. In the article analytical solution is searched for in general form and can be used for other similar mathematical problems.