Answer :
Given that:
this year you earned 75,500. Last year you earned $72,400.
So the rate of change in your earnings since last year:
[tex]\begin{gathered} \text{Avg}_{rate}=\frac{75500-72400}{1\text{ year }} \\ \text{Avg}_{rate}=\frac{3100}{1} \\ \text{Avg}_{rate}=3100 \end{gathered}[/tex]So the rate of change in your earnings since last year is $3100