About this tool
Enter the coefficients a, b and c to solve a quadratic equation. It shows the discriminant, both roots (real or complex), and the parabola's vertex, and falls back to the linear case when a is zero — all computed instantly in your browser.
Frequently asked questions
What happens when a = 0?
The equation becomes linear (bx + c = 0), so it reports the single root x = -c/b, or notes if there is no solution or every x works.
How are complex roots shown?
When the discriminant is negative the roots are conjugates, written in the form a + bi and a − bi.