The projected U.S. health expenditures (in trillions of dollars) in 2013 and 2015 is given in the following table, where t is measured in years, with t=1 corresponding to 2013. 1 Year, Expenditure, y 3 4.08 2.91 a. Calculate the slope. (Use three decimal points) b. Derive the equation giving the U.S. health-care spending by using the given data. (Enter your equation as y = mx + b) c. If the trend continues, what will be the U.S. health expenditures in year 2022. (Use three decimal points)