This looks like common core which is never straight forward.It seems as though they are asking for the perimeter and not area,since they used feet for the distance around instead of sq.ft.
You find the surface area of a cube by using A=6a^2
F(x) = -1.50x + 40.....basically, this is saying that Gloria has 40 bucks in her lunch account and each meal costs her 1.50.
By changing the -1.50 to -2.75 means she is paying more for her meals...the cost of a meal went up from 1.50 to 2.75.
