Final answer:
The rate of change is the slope of the line, which according to FIGURE A1, is 3.
Step-by-step explanation:
The question you've asked pertains to finding the rate of change, which in the context of the information provided, refers to the slope of a line on a graph.
The slope is described in FIGURE A1, where it is given that for every increase of 1 on the horizontal axis (x), there is a rise of 3 on the vertical axis (y).
Therefore, the slope or rate of change of the line is 3, as the line rises 3 units for each 1 unit it moves horizontally.