Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour after the time that she first checked
her outdoor thermometer. By 6 a.m., the temperature had fallen 21 degrees. Which expression can you use to find how many hours earlier she had first checked the thermometer
equals 
leaving you with x = 5 at a minimum. So 5x: 5 x 5 = 25