#### Answer

The relation is a function.
Domain: 4, 6, 8;
Range: 5, 7, 8.

#### Work Step by Step

Since there is only one $y$ for each $x$, the relation is a function.
The Domain is the set of all $x$'s, or what "you start with".
The Range is the set of all $y$'s, or what "you end up with", after each member of the Domain has been changed by the function.