A pet shop had 8 identical fish tanks in the shape of rectangular prisms. The width and height of each tank was (x - 7) inches and the length was 8 inches more than its width. The expression below shows the maximum amount of water which all the tanks together can hold
8(x + 1)(x - 7)2
What does the factor (x - 7)2 represent?
The total base area of all the tanks
The total surface area of each tank
The area of the rectangular base of each tank
The area of a square shaped side of the tank