Around 33:00, for the right-hand side of 'B', how did we obtain A'b/A'A  * A? The previous lesson, we obtained 'p' as aa'/a'a * b. How did the aa' *b in the numerator get switched to A'b * A?####[["A'b/A'A * A", 'Mathematical_Related_Concept', 'NEU'], ["'p'", 'Mathematical_Related_Concept', 'NEU'], ["aa'/a'a * b", 'Mathematical_Related_Concept', 'NEU'], ["aa' *b", 'Mathematical_Related_Concept', 'NEU'], ['numerator', 'Mathematical_Related_Concept', 'NEU'], ["A'b * A", 'Mathematical_Related_Concept', 'NEU']]