Concept:Intercepts are found where the graph crosses the axes, so one variable is set to zero. The inequality sign only describes the shaded region; the boundary line gives the intercepts.Explanation:Use the boundary equation 3x−z=9.Find the x-intercept by setting z=0:3x−0=93x=9x=3So the x-intercept is (3,0).Find the z-intercept by setting x=0:3(0)−z=9−z=9z=−9So the z-intercept is (0,−9).Thus, the intercepts written as (x,z) are (3,−9).Answer:A. (3,−9)