A car is traveling on a highway. the distance (in miles) from its destination and the time (in hours) is given by the equation d = 420 minus 65 t. what is the slope of the line represented by the equation? what is the practical meaning of the slope? a. m = 420; the total distance is 420 miles. b. m = 65; the car is traveling 65 miles per hour. c. m = negative 65; the car is traveling 65 miles per hour. d. m = negative 420; the total distance is 355 miles.