{ Quadratic Equation Solver }

// solve ax²+bx+c=0 — real and complex roots instantly

Solve quadratic equations ax²+bx+c=0 instantly. Find real and complex roots with step-by-step solutions, discriminant, and vertex. Free browser-based calculator.

ax² + bx + c = 0

ENTER COEFFICIENTS

For the equation ax² + bx + c = 0

Try:
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Enter coefficients and solve

Results will appear here with step-by-step breakdown

HOW TO USE

  1. 01
    Enter coefficients

    Fill in a, b, and c for your equation ax²+bx+c=0. Coefficient a must not be zero.

  2. 02
    Click Solve

    Hit the Solve button or press Enter. Results appear instantly with all working shown.

  3. 03
    Read the solution

    View real or complex roots, discriminant value, vertex, and the parabola graph.

FEATURES

Real Roots Complex Roots Step-by-step Graph Preview Vertex & Discriminant Copy Results

USE CASES

  • 📐 Homework and algebra practice
  • 🎓 Teaching and tutoring demonstrations
  • 🔢 Engineering and physics calculations
  • 💻 Quick verification of manual solutions

WHAT IS THIS?

A quadratic equation is any polynomial of the form ax²+bx+c=0 where a≠0. This solver uses the quadratic formula x = (−b ± √(b²−4ac)) / 2a to find exact roots — real or complex — instantly.

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FREQUENTLY ASKED QUESTIONS

What is a quadratic equation?

A quadratic equation is a second-degree polynomial equation of the form ax²+bx+c=0, where a, b, and c are constants and a≠0. It always has exactly two roots (counting multiplicity), which may be real or complex numbers.

What does the discriminant tell me?

The discriminant Δ = b²−4ac determines the nature of the roots: if Δ > 0 there are two distinct real roots; if Δ = 0 there is one repeated real root; if Δ < 0 the roots are complex conjugates with no real solutions.

Can I solve equations with decimal coefficients?

Yes. This solver accepts any numeric input including decimals and negative numbers for all three coefficients a, b, and c. Just type them directly into the input fields.

What are complex roots?

When the discriminant is negative, the square root of a negative number appears in the quadratic formula. The result is a pair of complex conjugate roots of the form p ± qi, where i = √(−1). These roots are real-world relevant in AC circuits, oscillations, and signal processing.

What is the vertex of a parabola?

The vertex is the turning point of the parabola y = ax²+bx+c. Its x-coordinate is −b/(2a) and the y-coordinate is c − b²/(4a). If a > 0 the vertex is a minimum; if a < 0 it is a maximum.

Is this tool free and private?

Completely free. All calculations run in your browser using JavaScript — no data is sent to any server, and no sign-up is required.

What Is a Quadratic Equation Solver?

A quadratic equation solver is a tool that finds the values of x that satisfy any equation of the form ax² + bx + c = 0. Instead of working through the quadratic formula by hand — which is error-prone and time-consuming — this calculator handles everything instantly: real roots, complex roots, the discriminant, the vertex, and even a visual parabola graph.

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The Quadratic Formula Explained

The quadratic formula is one of the most famous results in all of mathematics:

x = (−b ± √(b² − 4ac)) / 2a

Given any quadratic equation ax²+bx+c=0 with a≠0, this formula always produces the correct roots. The ± symbol means there are generally two roots — one computed with addition and one with subtraction. If those roots turn out to be identical (when the discriminant equals zero), the equation has a single repeated root.

Understanding the Discriminant (Δ = b² − 4ac)

Before you even compute the roots, the discriminant tells you what kind of solution to expect:

This diagnostic step is crucial in applied mathematics and engineering, where knowing the nature of the solution before computing it helps guide interpretation.

Real Roots vs Complex Roots

When Δ ≥ 0, the roots are real numbers that can be plotted on a number line and found as x-intercepts of the parabola y = ax²+bx+c. When Δ < 0, the formula requires the square root of a negative number. Rather than being undefined, this gives a complex number result of the form:

x = (−b ± i·√|Δ|) / 2a

Complex roots always appear in conjugate pairs: if p + qi is a root, then p − qi is the other. They are essential in electrical engineering (impedance), control theory (stability analysis), and quantum mechanics.

The Vertex of the Parabola

Every quadratic function y = ax²+bx+c traces a parabola. The vertex is its highest or lowest point, depending on the sign of a:

When a > 0, the parabola opens upward and the vertex is a minimum. When a < 0, it opens downward and the vertex is a maximum. This is used constantly in optimization problems — finding minimum cost, maximum area, or peak profit.

Step-by-Step Solution Breakdown

This solver shows all working so you can learn alongside the result:

  1. State the standard form: ax²+bx+c=0
  2. Compute the discriminant: Δ = b²−4ac
  3. Interpret Δ to determine root type
  4. Apply the quadratic formula with the correct sign handling
  5. Simplify to produce exact decimal values (or exact complex form)

Seeing each step makes the quadratic formula far easier to remember and apply independently.

Common Applications of Quadratic Equations

Quadratic equations appear throughout mathematics and applied science:

Why Use This Online Solver?

Manual calculation is straightforward for simple coefficients but quickly becomes error-prone with fractions, large numbers, or negative values. This browser-based solver eliminates arithmetic mistakes, handles complex roots automatically, displays all intermediate steps, and renders the parabola graph — all without any installation or sign-up. It runs entirely in your browser with no data sent to external servers.