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Quadratic Equation Solver - Find Roots Calculator

Free quadratic equation solver using the quadratic formula. Find roots, discriminant, and vertex of ax²+bx+c=0 equations instantly.

Quadratic Equation Solver

Solve ax² + bx + c = 0

The coefficient of x² (cannot be zero).

The coefficient of x.

The constant term.

Solutions

Enter your values to see results

and click the "Calculate" button

What is a Quadratic Equation?

A quadratic equation is a second-degree polynomial equation in the form ax² + bx + c = 0, where a ≠ 0. These equations can have two real solutions, one real solution (repeated root), or two complex solutions depending on the discriminant value.

How to Use This Calculator

  1. Enter coefficient a (the number before x²)
  2. Enter coefficient b (the number before x)
  3. Enter coefficient c (the constant)
  4. Click Solve to find the roots

Quadratic Formula

x = (-b ± √(b² - 4ac)) / 2a

The discriminant Δ = b² - 4ac determines: Δ > 0: two real roots, Δ = 0: one repeated root, Δ < 0: two complex roots.

Frequently Asked Questions

What does the discriminant tell us?
The discriminant (b² - 4ac) reveals the nature of solutions: positive means two distinct real roots, zero means one repeated root, negative means two complex conjugate roots.
Why can't 'a' be zero?
If a = 0, the equation becomes linear (bx + c = 0), not quadratic. A quadratic equation must have an x² term with a non-zero coefficient.
What is the vertex of a parabola?
The vertex is the highest or lowest point of the parabola. It occurs at x = -b/(2a), and the y-value is found by substituting this x into the equation.

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