Solve ax² + bx + c = 0. Real or complex roots, discriminant and vertex.
For ax² + bx + c = 0, the roots are x = (-b ± sqrt(b² - 4ac)) / 2a. The tool plugs in your a, b and c and returns both roots.
It is b² - 4ac. Positive means two distinct real roots, zero means one repeated real root, and negative means two complex (imaginary) roots, which the tool shows in a ± bi form.
The turning point of the parabola, at x = -b/2a. It is the minimum or maximum of the quadratic.