разрешимая проблема . Matemaatika terminibaas. Estonian Language Institute, Sõnaveeb 2026. https://sonaveeb.ee/search/unif//mat/%D1%80%D0%B0%D0%B7%D1%80%D0%B5%D1%88%D0%B8%D0%BC%D0%B0%D1%8F%20%D0%BF%D1%80%D0%BE%D0%B1%D0%BB%D0%B5%D0%BC%D0%B0/1/rus (11.11.2026)