How to use the Quadratic Equation Solver
- Enter a, b and c from ax² + bx + c = 0.
- Read the roots and the discriminant.
How it's calculated
Show the formula
x = (−b ± √(b² − 4ac)) ÷ 2a
Worked example
These are the example numbers the calculator opens with. Change any of them above to see your own result.
You enter
| a | 1 |
|---|---|
| b | -5 |
| c | 6 |
You get
| Roots | x = 3, 2 |
|---|---|
| Discriminant (b² − 4ac) | 1 |
| Root type | Two real roots |
Tips
- The discriminant (b² − 4ac) tells you the type of roots before solving.
Frequently asked questions
What does the discriminant tell me?
Positive: two real roots. Zero: one repeated root. Negative: two complex roots.
What if a is 0?
Then it is a linear equation, bx + c = 0, and x = −c ÷ b.