Enter three inequalities. Change the corresponding boundary input to the equation of a line similar to the equality.

1. After changing the inequalities, what are your initial observations of the shading? (Where is there no shading, some shading, darker shading?)
2. Are there any differences with lines? If so, what do the two types of lines represent?
3. Write down the intersection values for this system of inequalities. Are all three regions shaded at this point? (i.e. decide whether each point is a boundary point for the system of inequalities).
4. Change the inequalities and boundary equations and answer numbers 1-3 again.
5. Summary: How did you decide whether a point was a boundary point for all three regions?
Revised original worksheet by Terry Lee Lindenmuth