Texas Instruments TI-83 or TI-84

• 1). Press the "On" button to turn on the calculator.
  
  
• 2). Push the "Y=" button.
  
  
• 3). Enter the first inequality into "Y1=." Navigate to the symbol in front of "Y1."
  
  
• 4). Press "Enter" to adjust the shading of the equation. For an inequality with a "greater than" sign, such as "y > x - 3," press "Enter" twice. For an inequality with a "less than" sign, such as "y < x + 4," press "Enter" three times.
  
  
• 5). Press the down arrow button to navigate to "Y2." Repeat steps 3 and 4 for "Y2=" using a second inequality.
  
  
• 6). Press "Graph." The overlapping shaded area is the answer.
  
  

Hewlett-Packard HP-39g or HP-40g

• 1). Press the "On" button.
  
  
• 2). Press the "Aplet" button. Navigate to the "Dual Inequalities" aplet.
  
  
• 3). Press "Start." A note will appear on the screen. Hit the "Enter" button.
  
  
• 4). Enter the first inequality into "F1(X)=." Press "Enter" and type the second inequality into "F2(X)=."
  
  
• 5). Press the "Views" button. Select the types of inequalities from the list.
  
  
• 6). Press "OK." The double-shaded area is the answer.
  
  

Casio FX-9860G or FX-9860GII

• 1). Press the "AC" button to turn on the calculator.
  
  
• 2). Navigate to the "Graph" icon on the screen. Press the "Exe" button.
  
  
• 3). Press "F6" to navigate to the next screen. Select the "F" button that coincides with the inequality sign of the first inequality. Enter the first inequality and press the "Exe" button.
  
  
• 4). Repeat Step 3 for each additional inequality.
  
  
• 5). Press the "Shift" button. Then press the "Menu" button. Select "F1" to turn on inequality shading.
  
  
• 6). Press the "Exe" button, followed by the "F6" button. The shaded area is the answer.