Answer:
n = 0, n =2
Explanation:
Given
(n + 1) + 3(n - 1) = 2(n - 1)(n + 1) ← distribute parenthesis on both sides
n + 1 + 3n - 3 = 2(n² - 1), that is
4n - 2 = 2n² - 2 ( subtract 4n - 2 from both sides )
0 = 2n² - 4n ← factor out 2n from each term )
0 = 2n(n - 2)
Equate each factor to zero and solve for n
2n = 0 ⇒ n = 0
n - 2 = 0 ⇒ n = 2