The "solution" has the form of a graph. First, graph the line y=6 using a dashed (not solid) line. Shade the plane below this line.
Next, graph y = x-3, using a dashed line. This line has a y-intercept of (0,-3) and a slope of 1. Shade the area above this line.
The solution set is the area that has been shaded twice, once for each of the 2 given inequalities.