A chemist is performing an experiment by observing the effects when she combines two solutions. She monitors the temperature of the combined solution over the course of eight hours and records it in this table. Time (hours)012345678 Temperature (°F)20. 5019. 8217. 4214. 0210. 829. 5012. 2221. 6240. 82
The chemist can model the temperature with a polynomial function. During these eight hours, over what interval is the temperature decreasing?