As Part of His Job as Cost Analyst,John Kelly Collected

As part of his job as cost analyst,John Kelly collected the following information concerning the operations of the Machining Department:
$\begin{array}{lll}\text { Observation }&\text { Machine-hours }&\text { Total Operating Costs }\\\text { January } & 4,700 & \$ 43,000 \\\text { February } & 5,060 & 45,395 \\\text { March } & 4,180 & 42,535 \\\text { April } & 4,500 & 43,600 \\\text { May } & 4,250 & 42,890\end{array}$
Required:
a.Use the high-low method to determine the estimating cost function with machine-hours as the cost driver.
b.If June's estimated machine-hours are 4,300,calculate the total estimated costs of the Machining Department?