How do you solve the "N" in the following equation when the right side is squared (N+3)(2n+3)=(n+2)2+(n-2)2

If your equation is:
(n + 3)(2n + 3) = (n + 2)^2 + (n - 2)^2
then
2n^2 + 9n + 9 = n^2 + 4n + 2 + n^2 + 4
Foiled
2n^2 + 9n + 9 = 2n^2 + 4n + 6
Simplified

Next, move all "n" terms to one side and all number terms to the other.
2n^2 - 2n^2 +9n - 4n = 6 - 9

5n = -3
simplified
n = \frac{-3}{5}
answer