Answer:
Unit rate of change = -4.2°F/hour
Explanation:
Assuming a constant rate of change, a relationship between the change of temperature as a function of time (in hours) can be described as follows:
![r= ((36^oF - 57^o F))/(17 - 12)\\r= (-4.2^o F)/(hour)](https://img.qammunity.org/2020/formulas/mathematics/college/svuwn7f14xgpm6uw3xsamc36053pzkqnpy.png)
There is a temperature drop from 12pm to 5pm, which explains the rate of change being negative. This rate means that at every hour that goes by, the temperature drops by 4.2 degrees.