Answer:
(n -7)(4n + 8) = 0
Step-by-step explanation:
(a -b)² = a² - 2ab + b²
(2n - 5)² = 81
(2n)² - 2*2n*5 + 5² = 81
4n² - 20n + 25 = 81
4n² - 20n + 25 - 81 = 0
4n² - 20n - 56 = 0
4n² - 28n + 8n - 8*7 = 0
4n*(n -7) + 8*(n - 7) = 0
