A.) The tram’s elevation increased 5 meters a second so it is represented by positive 5. For 45 seconds it went higher up so we do 45x5 which equals 225. The tram’s elevation increased a total of 225 meters.
B.) The substance cooled 18 degrees Celsius total at a constant rate over a period of 9 hours. Since the rate is constant divide 18/9 which equals 2. However this change is decreasing so it will be represented by -2. The substance cooled 2 degrees Celsius per hour, so the change is -2.