Math | Graded Assignment | Unit Test, Part 2 | Exponential Functions

The graph shows the value of a car at different years after Gianna purchased it.

a) What is the average rate of change between years 3 and 7? Show your work and round to the nearest whole number.
b) What is the average rate of change between years 10 and 14 Show your work and round to the nearest whole number.
c) Is this a linear function? Using your answers from A and B, explain why or why not.