## Key Concepts

- To graph an inequality, first graph the related boundary line by replacing the given inequality symbol with the equality symbol to find its equation. Use a dashed line for a strict inequality. Then, test ordered pairs on either side of the boundary line and shade the side of the graph containing the point that satisfies the inequality equation.
- The solution to a system of linear inequalities is the region containing all the ordered pairs satisfying the system.
- You can verify whether a point is a solution to a system of linear inequalities in the same way you verify whether a point is a solution to a system of equations.
- Systems of inequalities have no solutions when boundary lines are parallel.
- Systems of inequalities can be used to model certain business situations.

## Glossary

**boundary line**- replacing the inequality symbol of an inequality with an equality symbol and graphing the resulting line will yield the boundary line of the inequality
**solution region**- all possible points [latex](x, y)[/latex] on a graph that satisfy an inequality or system of inequalities
**system of inequalities**- two or more inequalities with the requirement that solutions for the system must be solutions of all inequalities in the system