To determine which half-plane to shade, pick a test point that is not on the boundary. Check whether that point satisfies the inequality. If it does, shade the half-plane that includes the test point. If not, shade the other half-plane. The origin, (0, 0), is usually an easy test point as long as it is not on the boundary.
What is the graph of each inequality?
Step 1
Graph the boundary line
Step 2
Choose a test point, (0, 0). Substitute
Since
The boundary line is again
Shade the region opposite the region shaded above (for
You can also check the point (0, 0).
Since
Can you use the graph of
If you shaded above the line for
You can also inspect inequalities solved for y, such as