The Wonder Drug Company's Total Overhead Costs at Various Levels

The Wonder Drug Company's total overhead costs at various levels of activity are presented below:
$$\begin{array} { | l | r | r | } \hline \text { Month } & \text { Direct Labor } & \text { Total Overhead } \\\hline \text { September } & 15,000 & \$ 472,000 \\\hline \text { October } & 12,000 & 409,400 \\\hline \text { Nowember } & 18,000 & 542,000 \\\hline \text { December } & 21,000 & 604,700 \\\hline\end{array}$$

Assume that the overhead costs above consist of indirect labor,scheduling salaries,and maintenance.The breakdown of these costs for the month of November is as follows:
$$\begin{array} { | l | r | } \hline \text { Indirect labor } ( V ) & \$ 219,600 \\\hline \text { Maintenance } ( M ) & 197,400 \\\hline \text { Scheduling Salaries (F) } & 125,000 \\\hline & \$ 542,000 \\\hline\end{array}$$

Required:
(a. )Using the high-low method,determine the cost formula for maintenance.(b. )Express the company's total overhead costs in linear equation form.