1.
If the system of equations
x+y+αz=b2x+5y+2z=6x+2y+3z=3\begin{aligned} x + y + \alpha z &= b \\ 2x + 5y + 2z &= 6 \\ x + 2y + 3z &= 3 \end{aligned}

has infinitely many solutions, then 2α+3b2\alpha + 3b is equal to: