High $-$ Low Cost Estimation

Assume the local DHL delivery service hub has the following information available about fleet miles and operating costs:

Year Miles Operating Costs

$2010555,000$ ?$ $177,000$

$2011671,000206,000$

?

Use the high $-$ low method to develop a cost $-$ estimating equation for total annual operating costs. $($ Let X $=$ ?annual fleet miles. $)$