The owner of a retail store is tracking his inventory for an annual report. the graph below shows the remaining inventory for a particular item and the number of days that have passed since the stock was replenished. a store employee performs most of the daily unit counts, but the owner personally recorded that there were 61 units remaining after 3 days and 33 units remaining after 13 days. use these two data points to determine the equation for the line of best fit for the store's inventory. write the answer in decimal form.