Chapter P - P.2 - Linear Models and Rates of Change - Exercises - Page 18: 76

Linear equation: $C=0.51x+200$ Answer to the question: It will cost the company $269.87 if a sales representative drives 137 miles on any given day.

Linear equation: If $x$ is the number of miles driven, then one can multiply the number of miles driven with the amount paid per mile($0.51), and then add the 200 per day.