Well, looking at the graph, notice, its vertex is at 0,9, and it passes through the points -3,0 and 3,0, so hmm let's use 3,0, to get the equation of f(x)

10+8h=66
minus 10 both sides
8h=56
divide both sides by 8
h=7
worked 7 hours
In order of missing boxes, 15 and 76
Combine like terms / simplifying: 5p+4r+6s+7