1.
If the system of linear equations
2x+y−z=7,2x + y - z = 7,

x−3y+2z=1,x - 3y + 2z = 1,

x+4y+θz=k,x + 4y + \theta z = k,

where θ,k∈R\theta, k \in \mathbb{R} has infinitely many solutions, then θ+k\theta + k is equal to: