How to solve a quadratic equation on a GDC (graphical display calculator). This explanation uses the TI-82/83/84 calculators.

1. Press Y= to select the equation entry menu.

2. Enter your quadratic equation followed by ENTER.

3. You could press press GRAPH but it is better to press ZOOM then press 6 or select ZStandard.

4. You will see a display of your graph. Press ZOOM again then press 1 or select ZBox

5. Once back on the graph display, use the cursor keys and press ENTER at the top left and bottom right to create a zoom box

By repeated zooming in and use of the TRACE function you can obtain an accurate estimate of where the curve crosses the x-axis.

1. Press Y= to select the equation entry menu.

2. Enter your quadratic equation followed by ENTER.

3. You could press press GRAPH but it is better to press ZOOM then press 6 or select ZStandard.

4. You will see a display of your graph. Press ZOOM again then press 1 or select ZBox

5. Once back on the graph display, use the cursor keys and press ENTER at the top left and bottom right to create a zoom box

By repeated zooming in and use of the TRACE function you can obtain an accurate estimate of where the curve crosses the x-axis.

## Software/Applets used on this page

## Glossary

### equation

A statement that two mathematical expressions are equal.

### function

A rule that connects one value in one set with one and only one value in another set.

### gdc

graphic display calculator

### graph

A diagram showing a relationship between two variables.

The diagram shows a vertical y axis and a horizontal x axis.

The diagram shows a vertical y axis and a horizontal x axis.

### quadratic

A mathematical expression of the 2nd degree; having a x² term but no higher one.

### solve

To find the answer or solution to a problem.

### union

The union of two sets A and B is the set containing all the elements of A and B.