We have the points (-1,-1) and (1,0) on this graph if we had a solid line
The slope of this line is [ 0 - - 1 ] / [ 1 - -1] = [1]/ [2] = 1/2
So....using the point (1,0) and the slope we have either that
y < (1/2) ( x - 1) or y > (1/2)( x - 1)
Since the point (0,0) is in the feasible region, note that 0 > (1/2) ( 0 - 1) = 0 > -1/2 is true
So....the inequality is
y > (1/2) ( x - 1)
y > (1/2)x - 1/2
(1/2)x - y - 1/2 < 0 multiply through by 2
x - 2y - 1 < 0
