let's recall that the domain of a set is always the list of all x-coordinates in each pair.
[tex]\bf \stackrel{\large Domain\qquad \{2,-1,0,3,5\}}{(\stackrel{\downarrow }{2}~~,~~3),(\stackrel{\downarrow }{-1}~~,~~5),(\stackrel{\downarrow }{0}~~,~~-1),(\stackrel{\downarrow }{3}~~,~~5),(\stackrel{\downarrow }{5}~~,~~0)}[/tex]
