In a \(\triangle \mathrm{ABC}\), suppose \(y=x\) is the equation of the bisector of the angle \(\mathrm{B}\) and the equation of the side \(\mathrm{A C}\) is \(2 x-y=2\). If \(\mathrm{2 A B=B C}\) and the point \(\mathrm{A}\) and \(\mathrm{B}\) are respectively \((4,6)\) and \((\alpha, \beta)\), then \(\alpha+2 \beta\) is equal to
(1) 42
(2) 39
(3) 48
(4) 45