  A concise overview of the spectral theory of integral-functional operators is
provided. In the context of analysis, a technique is described for deriving
solutions to equations involving operators in a closed form. A constructive
theorem has been established, outlining a procedure for determining the
eigenvalues and eigenfunctions of these operators. Based on this foundation, an
analytical approach for generating solutions to a Volterra-type
integro-functional inhomogeneous equation is proposed.
