Question

The domain of the relation is

Answer 1

The domain of a relation is the set of all the x-terms of the relation.

Let's look at an example.

In the image provided I have attached a relation and we want to list the domain.

So, I will list all the x-terms. Notice however that I listed 7 once even though it appears twice in the relation. When listing the domain, you don't repeat the x-terms.