The domain of a relation consists of all the first elements (or inputs) from each ordered pair in that relation. In this case, the relation provided is:
- (3, 5)
- (8, 6)
- (2, 1)
- (8, 6)
To determine the domain, we extract the first elements from each pair:
- 3 from the pair (3, 5)
- 8 from the pair (8, 6)
- 2 from the pair (2, 1)
- 8 from the pair (8, 6) again (which has already been counted)
Thus, the first elements collected are: 3, 8, 2. Since sets do not allow duplicate values, we will only list each unique first element once. Therefore, the domain of the given relation is:
- 2
- 3
- 8
In summary, the domain of the relation is {2, 3, 8}.