In this clip the teacher leads a discussion about other possible representations for the box problem.
Box Problem Summary, Different Representations, Clip 1, 3:32
This along with the other 2 videos are examples of how a teacher can go through the various representations of the box problem, this one specific to the algebraic form.
Notice that the teacher gets lots of students engaged. She requires justification when they do not give it and points out that without a context, there are no longer any physical constraints on the formula. Since this did not come from the students, it was important for the teacher to bring this out.
To lead into the graphical representation, the teacher also points out how difficult it is to see the covariation in the algebraic form.
