So we got the function of the graph f(x) = 2^x + 1 what you will need to do first is find the y-coordinates corresponding to x=1 and x=3 which can be found by substituting into the function. After that we can find the average rate of change using y2-y1/x2-x1.
f(1)=2^1+1 which would be equal to 3
1,3
f(3)=2^3+1 which would be equal to 9
3,9
9-3/3-1=6/2
6/2=3
The average rate of change is 3.