roosevelt garage expects its utility costs to behave in relation to the number of oil changes as follows: number of oil changes utility costs 4,000 $ 6,000 6,000 $ 7,300 9,000 $ 9,600 12,000 $12,600 14,000 $15,000 roosevelt garage anticipates that it can provide the oil change service for $25 each. using the high-low method, what is the associated fixed cost with the utilities?