Answer
Linear, slope: $5$.
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:
$3-(-2)=5\\8-3=5\\13-8=5\\18-13=5$
Hence the difference of all consecutive y-values is $5$, which means that the slope is $5$.
Thus, the function is linear.
