Quadratic equation solver
Find the roots of a quadratic with real coefficients.
Formula
D = b² − 4ac; x = (−b ± √D)/(2a)
Coefficient a = 1 · Coefficient b = -3 · Coefficient c = 2
How to use
- Enter a, b and c from ax² + bx + c = 0.
- Keep |a| between 0.000001 and 1000000.
- Read both roots and the discriminant.
Examples
- x² − 3x + 2 = 0: x = 1 or 2.
- x² + 1 = 0: x = i or −i.
Frequently asked questions
What does a negative discriminant mean?
There are two complex conjugate roots; i² = −1.
Can a be zero?
No. That would be a linear equation. All coefficients are bounded to ±1000000.
Are displayed roots exact?
Roots are numerical approximations shown to 10 significant digits.
Sources
Updated: