Binomial Theorem Exam Style Question 2

Picked one by one from a mixed channel. Transcript check: both title readers certain; 5 of 5 sampled certain picks confirmed by transcript, none failed. Channel rule: Include only videos whose titles name a specific maths topic, method, exam paper or question, or a named puzzle (e.g. 'Simplifying surds', 'C2 Integration (2)', 'Solomon Paper K Q3'). Exclude exam-season encouragement, good-luck and tips messages, and any non-topic announcement-style uploads.