The range is the set of values that the function assumes, depending on the domain.
So, if the domain is
[tex]D = \{-3,\ -1,\ 4\}[/tex]
the range is
[tex]R = \{f(-3),\ f(-1),\ f(4)\}[/tex]
Here's the table with the values:
[tex]\begin{array}{c|c}x&3x-4\\-3&-13\\-1&-7\\4&8$\end{array}[/tex]
