Research studies show that the relationship between the tire pressure of a vehicle’s tires and the life of the tires is quadratic. The following table shows the recommended tire pressure of a car’s tires (in pounds per square inch) and its anticipated tire life (in thousands of miles).
Use a graphing or online regression calculator to find the quadratic function of best fit for this set of data. What is the value of a in this function?

Tire Pressure Tire Life
29 46.8
32 57.6
34 58.8
36 60.0
38 58.8
40 57.0
42 52.8

-0.00240947
-0.0240947
-0.240947
-2.40947