You can access the textbook and related materials through several educational platforms:
Алгебра, 9-класс, Н.Я.Виленкин, Г.С.Сурвилло, А.С.Симонов, А.И.Кудрявцев, 1998г. gdz po algebre 9 klassa pod redaktsiei vilenkina
— Fundamental operations and definitions of sets. You can access the textbook and related materials
— Deep dive into functional dependencies. gdz po algebre 9 klassa pod redaktsiei vilenkina
— Includes advanced methods for solving rational equations. Chapter XI: Sequences — Progressions and limits.
For physical copies, retailers like Ozon often carry new and used editions.