Greta's Gas Company charges residential customers $9 per month even if they use no gas, plus 64 per therm used. (A therm is a quantity of gas.) In addition, the company is authorized to add a rate adjustment, or surcharge, per therm. The total cost of using g therms of gas in a month is given by (a) Which term represents the rate adjustment? = Total cost 9+ 0.64g + 0.149g. What is the rate adjustment in cents per therm? i cents per therm (b) Is the expression for the total cost linear?