Quadratic Equation Calculator

How it's calculated

x = (−b ± √(b² − 4ac)) / 2a
D = b² − 4ac  (D > 0: two real roots, D = 0: one, D < 0: complex)

The discriminant decides the kind of roots. The vertex is the turning point of the parabola, at x = −b / 2a. The roots are computed in the numerically stable form (x₁ = q/a, x₂ = c/q with q = −(b ± √D)/2), so a tiny root next to a huge one keeps its digits.