Percentage Calculator
Find a percentage of a number, including the result after adding or subtracting it.
Math
Math
Quadratic Equation Calculator
Solve ax² + bx + c = 0 and identify the type of roots.
Enter your values
Your result
Solution type
Two distinct real roots
- First root
- 2
- Second root
- 3
- Discriminant Δ
- 1
An estimate based on your inputs. Review the assumptions and method below.
How does this calculator work?
The discriminant determines the number of real roots. A positive discriminant gives two distinct real roots; zero gives a repeated root; a negative value gives complex roots.
The formula
Δ = b² − 4ac; x = (−b ± √Δ) ÷ (2a)
What should you know?
- Coefficient a must not be zero, otherwise the equation is linear.
- For complex roots, the calculator displays the real part and the magnitude of the imaginary part.
Common questions
What does a zero discriminant mean?
Both roots have the same value, −b/(2a), called a repeated real root.
Why does i appear in some solutions?
i is the imaginary unit whose square is −1. It appears when the discriminant is negative.
Sources and verification
How do we choose formulas and check results?
Sources explain the method or its limits; they do not imply that the linked organizations endorse this calculator.