Quadratic Equation Calculator

Solve quadratic equations of the form ax² + bx + c = 0. Enter the coefficients below to calculate the roots, discriminant, vertex, and complete solution steps.

ax² + bx + c = 0
Must not be zero.
Example: x² − 5x + 6 = 0 uses a = 1, b = −5, c = 6 .

How to Solve a Quadratic Equation

A quadratic equation has the standard form:

ax² + bx + c = 0

where a, b, and c are numbers and a ≠ 0.

The Quadratic Formula

The roots of a quadratic equation can be found with the quadratic formula:

x = (−b ± √(b² − 4ac)) / 2a

The Discriminant

The expression inside the square root is called the discriminant:

D = b² − 4ac

The value of the discriminant determines the type of roots:

Example

Consider:

x² − 5x + 6 = 0

Here:

a = 1
b = −5
c = 6

The discriminant is:

D = (−5)² − 4(1)(6)
D = 25 − 24
D = 1

Since the discriminant is positive, there are two real roots:

x₁ = 3
x₂ = 2

Vertex Formula

For a quadratic function:

y = ax² + bx + c

the x-coordinate of the vertex is:

x = −b / 2a

Substitute this value into the original quadratic function to obtain the y-coordinate.