To answer your question accurately, I would need to see the graph or the image you are referring to. However, you can typically find the "initial value" from the y-intercept of the graph, which is where the graph crosses the y-axis (the value of the function when x = 0).
The "constant rate of change" can usually be determined by calculating the slope of the line, which is the change in y divided by the change in x over a specified interval.
To provide more specific answers, please describe the graph or provide the key values.