Blood Pressure and Age A research group developed the following mathematical model relating systolic blood pressure and age: P(r) = a+bin(x + 1). where P(c) is pressure, measured in millimeters of mercury, and c is age in years. By examining Guilford County hospital records, they estimate the values for Guilford County to be a = 44 and b = 28. Using this model, estimate the rate of change of pressure with respect to time after 15 years. Round to the nearest hundredth (2 decimal places). millimeters per year