2. The equation can be rewritten in terms of time t and Temp T as:
T=-5.01852 t + 96.824
This line is the one you should use when predicting the temprature corresponding to a given cooling time.
What you want is the line that gives the cooling time to a given temprature. You can get this by doing what you did before but with the columns reversed, when it will give you an equation which will be:
where a and b are numbers given by the regression calculation.
You can instead just rearrange the equation you already have, but it will not be as good at predicting the time to cool to a given temprature but that may not matter too much in this case.