Enter coefficients

a
For a true quadratic, a ≠ 0
b
Any real number
c
Any real number

Understand the quadratic formula

The quadratic formula solves any polynomial equation of degree two: ax² + bx + c = 0, where a, b, and c are real numbers and a ≠ 0. It gives the solutions (roots) directly without factoring or completing the square.

Formula: x = (−b ± √(b² − 4ac)) / (2a)

Discriminant and nature of roots

The discriminant Δ = b² − 4ac determines the type of roots:

Δ > 0: Two distinct real roots.
Δ = 0: One real double root (the parabola touches the x-axis).
Δ < 0: Two complex conjugate roots (the parabola does not cross the x-axis).

Vertex and axis of symmetry

The axis of symmetry is x = −b/(2a). The vertex occurs at (h, k) where h = −b/(2a) and k = f(h) = a·h² + b·h + c. This is essential in optimization and curve analysis.

Common pitfalls

Zero a: If a = 0, the equation is linear (bx + c = 0). Use x = −c/b.
Rounding too early: Keep full precision through steps, then round final results.
Sign mistakes: Carefully apply −b and ± in the numerator.

Who benefits

Students use it for algebra and calculus prep, educators for demonstrations, engineers for quick checks, data scientists for model diagnostics, and analysts for curve-fitting sanity checks. This tool is global and language-agnostic—no regional formats required.

How to read the results

Roots: Real or complex solutions shown with clear notation.
Discriminant: Explains why roots are real or complex.
Vertex & axis: Useful for graphing and optimization.
Factor form (if real): Displays a(x − r₁)(x − r₂) when possible.

FAQs

HOW TO solve a quadratic equation using this calculator?

Enter a, b, and c, then select Calculate. You’ll get roots, discriminant, vertex, axis of symmetry, and the nature of roots instantly.

HOW TO check if my equation is quadratic?

If a ≠ 0, it’s quadratic. If a = 0, the tool switches to linear mode and solves bx + c = 0.

HOW TO handle complex roots?

When Δ < 0, the calculator shows x = p ± qi (real and imaginary parts). Use both values in applications requiring complex arithmetic.

HOW TO find the vertex and axis?

Axis is x = −b/(2a). Vertex is (h, k) with h = −b/(2a) and k = f(h). Both are auto-computed and displayed.

HOW TO improve accuracy?

Enter coefficients with full precision and avoid rounding intermediate steps. The calculator computes at double precision.

HOW TO use this tool globally?

The tool is entirely client-side and country-neutral. It uses standard mathematical notation with no locale-specific formats.

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