The point which does not lie in the solution region of $2x - y ≤4$ is

(1, -1) (5, 1) (0, 2) (1, 1)

(5, 1)

$2x - y ≤4$ for $(x,y)=(5,1)$ $2×5-1≤4⇒10-1≤4⇒9≤4$  (false) hence (5, 1) is not in solution region