Algebra guide
How to Use the Quadratic Formula
For ax² + bx + c = 0, the quadratic formula finds the roots.
x = (−b ± √(b² − 4ac)) / 2a
Worked example: x² − 5x + 6 = 0
- Identify a = 1, b = −5, c = 6.
- Discriminant: b² − 4ac = 25 − 24 = 1.
- Substitute: x = (5 ± √1) / 2.
- Compute both values: x = 3 and x = 2.
Discriminant > 0 gives two real roots, = 0 gives one repeated real root, and < 0 gives complex roots.