The cost C, in dollars, of renting a moving truck for a day is given by the function C(x)=0.20x+45, where x is the number of miles driven. (a) What is the cost if a person drives x=80 miles? (b) If the cost of renting the moving truck is $60, how many miles did the person drive? (c) Suppose that a person wants the cost to be no more than $150. What is the maximum number of miles the person can drive? (d) What is the implied domain of C?