Graphing

Systems of Inequalities

Using a Graphing Calculator

A graphing calculator can be used to find or check solutions to a system of inequalities. A graphing calculator can be used to graph the lines as an alternative to graphing the equations by hand. The following example will show graphing using a TI-84 calculator.

Example Solve the following system:

2x - y > -3
4x + y < 5

Step 1. Re-write the inequalities to isolate "y."

y < 2x + 3
y < -4x + 5

Step 2. Replace the inequality sign with an equal sign.Press the [y=] button on the graphing calculator and enter the two functions as:

y = 2x + 3 and y = -4x + 5