Question

N(2n+1)-(n-6)=2n(n+1)+10

Answer 1

n = -2. Is that what you're trying to figure out?

Answer 2

2n^2 + n -n + 6 = 2n^2 + 2n + 10
6 = 2n + 10
-4 = 2n
-2 = n