A meteorologist creates a parabola to predict the temperature tomorrow,
where x is the number of hours after midnight and y is the temperature
(in degrees Celsius). At midnight, the temperature is 9.6°C. At 5 a.m.
(x = 5) and 8 p.m. (x = 20), the temperature is 0°C.
a) Write a function that models the temperature over time.
b) What is the coldest temperature?