Challenge 1: Adjusting a Shared Cut Point Between Two Clips — Solution Walkthrough

The fitting edit type:

Roll.

Why, per this chapter's own material:

A Roll edit adjusts the cut point between two adjacent clips
simultaneously — lengthening one clip while shortening the other by
the exact same amount, without moving anything else on the timeline.
This matches the described task precisely: trimming a few frames off
the end of one clip and adding them to the start of the next is
exactly shifting the shared boundary between the two clips, with
everything else on the timeline staying fixed.

Why Ripple wouldn't fit here:

Per this chapter's own material, Ripple trims a clip's own edge and
shifts every subsequent clip on the track to close the resulting gap
— it doesn't simultaneously lengthen the neighboring clip to compensate
the way Roll does; it would instead shift the timing of everything
after the trim point, which isn't what's needed here.

Why Slip wouldn't fit either:

Slip changes which portion of the source footage is shown within a
clip's own existing length and position — it doesn't touch the shared
boundary between two clips at all, so it wouldn't accomplish the
described task of redistributing time between two adjacent clips.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise is a direct, practical application of this chapter's own
three-way trim distinction to a scenario matching Roll's own specific
definition, correctly ruling out the other two edit types by name.