Answer
Rate of change=0
The percent of pay raise is constant from year to year (at 3%).
Work Step by Step
To calculate the rate of change between two points $(a,f(a))$ and $(b,f(b))$, where $b \gt a$, we use the formula:
rate of change$=\frac{f(b)-f(a)}{b-a}$
We use the two points $(0,3)$ and $(4,3)$:
rate of change$=\frac{3-3}{4-0}=0$
Thus the percent of pay raise is changing at a rate of 0 per year. In other words, the percent of pay raise is constant from year to year (at 3%).