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Quadratic Formula Calculator

Enter coefficients (a, b, c) from a quadratic polynomial to instantly find real or complex roots, the discriminant, and vertex coordinates.

Quadratic Target: ax² + bx + c = 0

a ≠ 0
x² +x += 0

Roots (One Real Root)

x = -2

Discriminant (Δ)

0

Vertex (x, y)

(-2, 0)

Quadratic Formula Calculator: Solve Polynomials Instantly

The quadratic equation is a fundamental pillar of classical algebra and physics. Whether you are plotting the parabolic trajectory of a launched projectile, optimizing area constraints in architecture, or analyzing cost-profit margins in economics, quadratic polynomials are inescapable. The Calculay Quadratic Formula Calculator instantly processes standard form equations (ax² + bx + c = 0) to find the precise real or complex roots of any parabola.

The Standard Quadratic Equation

A quadratic equation is a second-degree polynomial, meaning its highest exponent is exactly 2. The standard mathematical form is always written as:

ax² + bx + c = 0

Where x represents an unknown variable, and a, b, and c are known constant coefficients (with the absolute rule that 'a' cannot equal zero).

How the Quadratic Formula Works

When a quadratic polynomial cannot be easily factored using simple mental math, mathematicians rely on the universal Quadratic Formula to find the x-intercepts (the roots):

x = [ -b ± √(b² - 4ac) ] / 2a

Understanding the Discriminant (b² - 4ac)

The expression locked inside the square root is known as the Discriminant (often denoted by the Greek letter Delta, Δ). The value of the discriminant instantly tells you the nature of the parabola's roots before you even finish the calculation:

  • Positive Discriminant (Δ > 0): The equation has two distinct real roots. The parabola crosses the x-axis at exactly two different points.
  • Zero Discriminant (Δ = 0): The equation has exactly one real root (a repeated root). The vertex of the parabola rests exactly on the x-axis, touching it at a single point.
  • Negative Discriminant (Δ < 0): The equation has two complex (imaginary) roots. The parabola is floating entirely above or below the x-axis and never explicitly intersects it in the real plane.

The Vertex

The calculator also provides the exact (x, y) coordinate of the parabola's vertex. The vertex is the absolute highest or lowest point of the curve. The x-coordinate of the vertex is found at -b / (2a), lying exactly halfway between the two roots along the axis of symmetry.