The solution of two intersecting lines is the point that both share in common. From a point of view, it is the point where the two lines meet. In this case, the point is in quadrant 1, or Region B.
I believe it is region D, since there is a -1/3 time x. Hence, the x coordinate is in the negatives. Also, the rest of the numbers are positive, so the plot will not go below the y-axis.
