Most of mathematical physics problems can be translated into solve one partial differential equation or more with specific initial conditions and boundary conditions. This is called the boundary value problem for the differential equations. This paper studies the solution of systems of hyperbolic and parabolic partial differential equations assuming some boundary conditions in different domains in the plane xoy. In this paper we have proved theorem about the existence and uniqueness of the solutions. This article is considered to be a continuation to the works of Alimove, Ssallah Aldinov, Gooraev and Alhamad.......