Question 986964
Hi there,
Length = (20 - 2x)
Width = (20 - 2x)
Height = x
.........
Volume = (20 - 2x)(20 - 2x) x
Volume = 4x^3 - 80x^2 + 400x
............
Surface Area:
4x^2 - 80x + 400  (Base)
4(20x - 2x^2) (Sides)
80x - 8x^2 (Sides) 
Total =
-4x^2 + 400
...........
Hope this helps :-)