Why? Because we draw a dashed line through x = -1/2 = -0.5 on the horizontal number line (aka x axis). Then we shade to the right of this dashed line. The shaded region represents all points that make the inequality true. For example, the point (0,0) is in the shaded region. It has an x coordinate of x = 0 which is larger than -1/2
Side note: the dashed line says "points on this boundary do not count as solutions". So any point with an x coordinate of -1/2 does not count.
