Matrices And Determinants

Let \(A = \left[ {\matrix{ 1 & 2 \cr { - 1} & 4 \cr } } \right]\). If A^\(-\)1 = \(\alpha\)I + \(\beta\)A, \(\alpha\), \(\beta\) \(\in\) R, I is a 2 \(\times\) 2 identity matrix then 4(\(\alpha\) \(-\) \(\beta\)) is equal to :