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 $2006560,000$ $$177,0002007688,000209,000$ Use the high$-$low method to develop a cost$-$estimating equation for total annual operating costs. $($Let X $=$ annual fleet miles.$)$ Total annual costs $=$ $ $0=+$ $ $0$