Brian is working on the budget for his summer window$-$washing business, trying to figure out what his total costs are going to be for

the season. He has monthly data from last summer, so he decided to start with that. Using the observations below, use the high$-$low

method to estimate a total monthly cost function for Brian's business.

$($Round answers to $2$ decimal places, e$.$g$.15\mathrm{.}25.)$

$Y=$$

$x+$$