Algebra-1

Universal Set: The universal set, denoted by U, is the collection of all possible elements under consideration in a particular context or problem. In this case, the universal set is given as {1, 2, 3, 4, 5, 6, 7, 8, 9}.

Complement: The complement of a set B, is the set of all elements in the universal set that are not in B. In other words, it consists of the elements that belong to the universal set but do not belong to B.