A high school is expanding its football field in order to allow other sports to be played on the field. The school will also be installing artificial turf, which costs $ 4.75 per square foot, on the entire field. The current football field is 360 feet long and 160 feet wide. The number of feet, x , by which the length of the field will be expanded is twice the number of feet by which the width of the field will be expanded. Which function f ( x ) represents the cost of artificial turf for the entire field?