Answer:
0x8y
Step-by-step explanation:
x is negative so i turned it into a negative number b, y is - so 8 and o is slope
Check the picture below, that's just an example of a parabola opening upwards.
so the cost equation C(b), which is a quadratic with a positive leading term's coefficient, has the graph of a parabola like the one in the picture, so the cost goes down and down and down, reaches the vertex or namely the minimum, and then goes back up.
bearing in mind that the quantity will be on the x-axis and the cost amount is over the y-axis, what are the coordinates of the vertex of this parabola? namely, at what cost for how many bats?

![\bf \left( -\cfrac{-7.2}{2(0.06)}~~,~~390-\cfrac{(-7.2)^2}{4(0.06)} \right)\implies (60~~,~~390-216) \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill (\stackrel{\textit{number of bats}}{60}~~,~~\stackrel{\textit{total cost}}{174})~\hfill](https://tex.z-dn.net/?f=%5Cbf%20%5Cleft%28%20-%5Ccfrac%7B-7.2%7D%7B2%280.06%29%7D~~%2C~~390-%5Ccfrac%7B%28-7.2%29%5E2%7D%7B4%280.06%29%7D%20%5Cright%29%5Cimplies%20%2860~~%2C~~390-216%29%20%5C%5C%5C%5C%5B-0.35em%5D%20%5Crule%7B34em%7D%7B0.25pt%7D%5C%5C%5C%5C%20~%5Chfill%20%28%5Cstackrel%7B%5Ctextit%7Bnumber%20of%20bats%7D%7D%7B60%7D~~%2C~~%5Cstackrel%7B%5Ctextit%7Btotal%20cost%7D%7D%7B174%7D%29~%5Chfill)
First you must find X by setting the sides equal to each other. from that you know x=4 then plug that into the w/ they give you the Equation to. = 6then multiply by 2 and you get 12
The answer is $246.73 Just for whoever is trying to pass those Apex tests!