5. A vehicle was purchased for $15 000 in 2005. The value of the vehicle can be modelled by the exponential function: y = 15 000(0.82)* where y represents the value in dollars and represents the time, in years, after 2005 (year 0). a) How does the value of the vehicle change over time (increase or decrease)? Explain how you know. (2 marks) b) Estimate the value of the vehicle in 2015. Show your work. (2 marks)