Quadratic Equation

Solve a quadratic equation ax²+bx+c=0 and inspect its real or complex roots.

Enter your values in the calculator fields to get an instant result.

Calculator guide

Solve a quadratic equation ax²+bx+c=0 and inspect its real or complex roots.

Formula or method

x = (−b ± √(b²−4ac))/(2a); the discriminant D=b²−4ac determines the root type.

How to use this calculator

  1. Enter coefficients a, b, and c.
  2. Confirm a is not zero.
  3. Review both roots and the discriminant.

Worked example

For x²−5x+6=0, D=25−24=1 and roots are (5±1)/2, or x=3 and x=2.

Understanding the result

D>0 gives two real roots, D=0 one repeated real root, and D<0 a complex-conjugate pair.

Limitations and assumptions

  • This tool solves the equation represented by the entered coefficients only.
  • Very large or nearly equal coefficients can introduce floating-point rounding.

Frequently asked questions

What if a is zero?

The equation becomes linear and is not quadratic.

What does a negative discriminant mean?

There are no real x-intercepts, but complex roots still exist.

How can I check a root?

Substitute it into ax²+bx+c; the result should be near zero.

Sources

Educational information only; verify important decisions with a qualified professional.