Quadratic Equation Solver
Find roots for ax² + bx + c = 0
Calculation Results:
How to Use the Quadratic Solver
While the TI-84 Plus graphing calculator has a built-in Polynomial Root Finder app (PolySmlt), sometimes you need a quick solution without navigating through menus. This tool replicates the core functionality of solving for x in the standard form equation ax² + bx + c = 0.
Understanding the Discriminant
The key to solving these equations on the TI-84 or by hand is the discriminant (b² – 4ac). This value tells you what kind of roots to expect:
- Positive Discriminant: There are two distinct real solutions where the graph crosses the x-axis.
- Zero Discriminant: There is exactly one real solution (the vertex of the parabola touches the x-axis).
- Negative Discriminant: The solutions are complex numbers involving imaginary parts (i), meaning the graph does not touch the x-axis.
Steps for TI-84 Plus Users
If you want to verify these results on your physical device, follow these steps:
- Press the
[APPS]key. - Scroll to PolySmlt and press
[ENTER]. - Select 1: Polynomial Root Finder.
- Enter your degree (2 for quadratic) and the values for a, b, and c.
- Press
[GRAPH](F5) to see the solutions.