How to Solve Quadratic Equations on a TI-84 Calculator

Introduction

Quadratic equations can be solved with factoring, the quadratic formula, or graphing. A TI-84 can help you estimate roots and check exact algebra.

Step-by-step graphing method

1. Move all terms to one side so the equation equals zero.
2. Press Y=.
3. Enter the quadratic expression in Y1.
4. Press GRAPH.
5. Look for x-intercepts.
6. Use trace or zero-finding features to estimate the roots.

Practical example

For x^2 - 5x + 6 = 0, graph y = x^2 - 5x + 6. The graph crosses the x-axis at 2 and 3, matching the factored form (x - 2)(x - 3).

Common mistakes

• Graphing both sides without understanding what intersection means.
• Forgetting to set the equation equal to zero.
• Trusting a graph estimate when the problem asks for exact roots.
• Using a window that hides one intercept.

FAQ

Can a TI-84 solve every quadratic exactly?

It can help check solutions, but exact answers may require algebra.

What if the graph does not cross the x-axis?

The quadratic may have no real roots, or your window may hide them.

What related article should I read?

Read how to graph on a TI-84 and practice on the homepage calculator.