Answer:
b: Â See first attached photo
c:  V = x²y
d and e:  V = x(3 - 2x)²
f: Â 2 cubic feet
Step-by-step explanation:
a: Â Sketch several boxes and calculate the volumes. Â
b: Â See first attached photo a diagram of this situation
The diagram is a square. We are cutting out squares from the corners.  We don't know the size of the square yet. The side lengths were 3, but now they are 3 - 2x  (since each corner has one side of the square, there are 2 sides of the cut out square on each side of the larger square)
c: The equation for volume is:  V = x²y
The length and width of the box are the x values, the height would be the y value
d and e:  It wants the equation for the volume for our situation.  The base of the box is (3 - 2x)(3 - 2x) or (3 - 2x)².  The height of the box is x, so the volume is
V = x(3 - 2x)² Â
f: Â Take the derivative, find the critical values, then plug that into x and solve for the volume. Â See second attached photo for the work for finding the x value that maximizes the box, and the third attached photo for the evaluation of the maximum volume...