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Quadratic Formula Calculator

Solve quadratic equations ax²+bx+c=0 with step-by-step solution, discriminant, and roots

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Quadratic Formula Calculator

Solve quadratic equations ax²+bx+c=0 with step-by-step solution, discriminant, and roots

Enter Coefficients

ax² + bx + c = 0

x² - 5x + 6 = 0

Quick examples:

Solution

Discriminant (Δ)

1

Two distinct real roots

Sum of roots

5

= -b/a

Product of roots

6

= c/a

x₁

3

x₂

2

Vertex of parabola

(2.5, -0.25)

Axis of symmetry: x = 2.5

Step-by-step solution

  1. 1. Standard form: ax² + bx + c = 0
  2. 2. a=1, b=-5, c=6
  3. 3. Δ = b² - 4ac = (-5)² - 4(1)(6) = 25 - 24 = 1
  4. 4. Δ > 0 → Two distinct real roots
  5. 5. x = (-b ± √Δ) / 2a = (5 ± √1) / 2
  6. 6. x₁ = 3, x₂ = 2

The quadratic formula calculator solves equations of the form ax² + bx + c = 0. Enter the three coefficients and get the discriminant, real or complex roots, vertex of the parabola, and a full step-by-step derivation using the quadratic formula x = (−b ± √(b²−4ac)) / 2a.

How to Use

  1. 1Enter the coefficient a (the x² term)
  2. 2Enter the coefficient b (the x term)
  3. 3Enter the constant c
  4. 4Read the discriminant — positive means two real roots, zero means one repeated root, negative means two complex roots
  5. 5Copy the solution with the Copy button

Frequently Asked Questions

What is the quadratic formula?
The quadratic formula is x = (−b ± √(b²−4ac)) / (2a). It gives the solutions to any equation of the form ax² + bx + c = 0, where a ≠ 0.
What does the discriminant tell you?
The discriminant Δ = b² − 4ac determines the nature of the roots: Δ > 0 gives two distinct real roots; Δ = 0 gives one repeated real root; Δ < 0 gives two complex conjugate roots.
What if a = 0?
When a = 0 the equation reduces to bx + c = 0, which is linear (not quadratic). The calculator handles this case and solves for x = −c/b.