Question

Solve graphically : x ≥ 0 and y ≤ 0.

Answer 1

Consider the lines whose equations are x = 0, y = 0.These represents the equations of Y-axis and X-axis respectively, which divide the plane into four parts.
Since x ≥ 0,  y ≤ 0, the solution set is in the fourth quadrant which is shaded in the graph.