Answer:
(b-1)²-9
= 4[(b - 1)(b - 1)] - 9
= 4[b² - b - b + 1] - 9
= 4(b² - 2b + 1) - 9
= 4b² - 8b + 4 - 9
= 4b² - 8b - 5
Hope this helps!
