The document discusses expressions with radicals (irrational expressions) in algebra. It covers resolving equations and inequalities with radicals, finding the set of admissible values, and three methods for solving irrational equations - using powering and checking solutions, changing variables, and using conjugates. It also discusses the key steps for solving irrational inequalities: finding the set of admissible values, giving logical meaning, eliminating radicals, and finding the solution set by intersecting the results of the previous steps.