Answer
Linear
slope $=-3$
Work Step by Step
A function is linear if there is a constant rate of change of the function, which is also called the slope.
Note that:
$1-4=-3\\
-2-1=-3\\
-5-(-2)=-3\\
-8-(-5)=-3$
Hence, the difference of all consecutive y-values is $-3$, which means that the slope is $-3$.
Thus, the function is linear.