Volume of a lidless box

Instructions

1. Slide the red point and learn how the volume of the box varies as the length of the red squares in the corners of the sheet of paper varies. 2. Slide the black point named "Faces" to learn how the box is built one the corners are cut into four congruent squares. 3. Let be the length of the sides of the squares cut in the corners of the sheet of paper. Write the polynomial function which describes the volume of the box built in this way. What is its domain (in this context)? What is its range (in this context)?