1.
Let AA be a 2×22 \times 2 matrix with real entries such that AT=αA+IA^T = \alpha A + I, where αR{1,1}\alpha \in \mathbb{R} \setminus \{-1, 1\}. If det(A2A)=4\det(A^2 - A) = 4, the sum of all possible values of α\alpha is equal to: