Dear al noor,
For the 2nd question part (a), once again, your graph is a parabolic curve with the symmetry at x=30. Therefore, that's where your maximum point will lie which is (30,400). It should begin at -500 and end there as well therefore, the starting point of the graph would be (0,-500) and the end point would be (60,-500)
EDIT : For the 2nd question part (c), the expression should be (x-30)^2 -400. There shouldn't be a -x outside. The connection is as stated by astar.
I'm trying to figure out the part where they ask for the loss when toys are given away though.