Information about Brightman Corporation's utility cost for the first six months of 2001 follows. The company's cost accountant wants to use the high-low method to develop a cost formula to predict future charges and believes that the number of machine hours is an appropriate cost driver.
$$
\begin{array}{lcr}
\text { Month } & \begin{array}{c}
\text { Machine } \\
\text { Hours }
\end{array} & \begin{array}{r}
\text { Utility } \\
\text { Expense }
\end{array} \\
\hline \text { January } & 68,000 & \$ 1,220 \\
\text { February } & 62,000 & 1,172 \\
\text { March } & 66,300 & 1,014 \\
\text { April } & 64,000 & 1,195 \\
\text { May } & 67,500 & 1,300 \\
\text { June } & 62,500 & 1,150
\end{array}
$$
a. What is the cost formula for utility expense?
b. What would be the budgeted utility cost for September 2001 if 64,750 machine hours are projected?