Question 366578
Hint: The quadratic in the form {{{y=a(x-h)^2+k}}} gives you the vertex (h,k). At this vertex is the highest/lowest point. Since we want to minimize costs, this means that (h,k) is the lower point. Also, this means that {{{a<0}}} (ie 'a' is negative). Let me know if this is enough to get started.