Is buying good grades in exchange for exemption from some duties and tasks and for raising one's rank considered a bribe? What is the ruling on that?

What was mentioned about raising the grade of one who bought the notebook (study guide) in the exam and overlooking his mistakes, and exempting him from assignments and projects, unlike one who did not pay, is impermissible. Buying the notebook in such a case falls under the meaning of forbidden bribery.