The domain of a relation is the set of all the first elements (or x-coordinates) of the ordered pairs in the relation.
For the relation \({(4,5), (-3,8), (9,-10)}\), the first elements are:
- From the pair \((4,5)\), the first element is \(4\).
- From the pair \((-3,8)\), the first element is \(-3\).
- From the pair \((9,-10)\), the first element is \(9\).
So, the domain of the relation is:
\[ {4, -3, 9} \]