20. The monthly cost of driving a car is determined by the distance driven. Lin cost $380 in May, driven 770 km, and $460 in June, driven 1290 km. (a) Find the function of the monthly cost C for the distance d driven. Assume that it is appropriate to express it as a linear function. (b) Using (a), find the cost per month for driving 2,400 km. (c) Draw a graph of the linear function. What does slope mean? (d) What does the C-intercept mean? (e) Why is it appropriate to express this situation as a linear function