1.
For α,βR\alpha, \beta \in \mathbb{R} and a natural number nn, let An=n2r1+α2r2n2β3r23n(3n1)2A_n = \begin{vmatrix} n^2 & r & 1+\alpha \\ 2r & 2 & n^2-\beta \\ 3r-2 & 3 & \frac{n(3n-1)}{2} \end{vmatrix}. Then 2A10A92A_{10} - A_9 is