Subtract 80 _ 65 and get 15
For this case we have the following variables:
x: the number of minutes of television Sam watched each day
y: the number of minutes she spent exercising
Then, we have the following function that models the problem:

if she spends 30 minutes watching television we have x = 30.
Substituting in the given equation we have:

Answer:
the best prediction for the number of minutes of exercising Sam will do if she spends 30 minutes watching television that day is:
72 minutes
aerage rate of change is just the slope from the endpoints of teh interval
ie 
assuming you mean 
evalaute f(5) and f(1)
f(5)=480(0.3)^5=1.1664
f(1)=480(0.3)^1=144
average rate of change=(1.1664-144)/(5-1)=-35.7084
the average rate of change of the function on the interval x=1 to x=5 is -35.7084
The greatest angle is a and d they are equal