The y-interception is y=900 or(0,900) which means that a car must travel 900 miles for the final destination. And every hour driven is 50 miles.
The average rate of change isIt represents how many miles per one hour changes the distance from a destination.
Domain of this function if the car traveled the same rate until it reached its destination:
0=-50x+900
50x=900
x=900/50=18
Domain: x∈ [0, 18].