1.
Let B=(0110)B = \begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix} and AA be a 2×22 \times 2 matrix such that A=B1A = B^{-1}. If BCB1=ABCB^{-1} = A and C2+αC+βI=0C^{2} + \alpha C + \beta I = 0, then 2βα2\beta - \alpha is equal to: