The tutor shows a technique for factoring expressions that contain brackets. The technique may be called compound factoring.

Example: factor (2x-1)² – 5(2x-1) – 24

Solution:

1. Substitue A for (2x-1), then rewrite:
   A² – 5A – 24
2. The expression is now an easy trinomial (see my post here) and factors like so:
   (A – 8)(A + 3)
3. Now resubstitute (2x-1) for A:
   ((2x-1) -8)((2x-1) + 3)
4. Simplifying, we get
   (2x-9)(2x+2)

The substitution method is very useful for this type of question:)

Source:

Travers, Kenneth et al. Using Advanced Algebra. Toronto: Doubleday Canada, 1977.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.