If you see a formula used that you don't recognize, go back to that chapter in the book.
The 2017 Makarychev textbook (edited by S.A. Telyakovsky) is part of the "Prosveshchenie" series. It’s important to match the year because: Exercise numbering often shifts between editions.
Newer versions may include updated OGE (ОГЭ) prep questions.