2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/213719In this paper, we obtain the general solution and the generalized Hyers-Ulam Rassias stability of the functional equation $$3(f(x+2y)+f(x-2y))=12(f(x+y)+f(x-y))+4f(3y)-18f(2y)+36f(y)-18f(x).$$Functional Analysis39B82,39B52text