#### Answer

The relation is a function.
Domain: {3, -5, 7, 4};
Range: {-2, 1, 9}.

#### Work Step by Step

The relation is a function, as there is no more than one $y$ for each $x$.
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.