To solve ax squared plus bx plus c equals 0, enter a, b and c into the Quadratic Equation Solver. It shows the discriminant and both real roots, using the quadratic formula x = (-b plus or minus the square root of b squared minus 4ac) divided by 2a.
How to use the Quadratic Equation Solver
- Rewrite your equation as ax^2 + bx + c = 0.
- Enter the values of a, b and c.
- Read the discriminant and the roots.
- Substitute a root back into the equation to check it.
Worked example
For x^2 – 5x + 6 = 0, a is 1, b is -5 and c is 6. The discriminant is 25 – 24 = 1, so the roots are x = 2 and x = 3.
Tips and common mistakes
- If the discriminant is negative there are no real roots.
- If it is zero there is exactly one repeated root.
- The value of a cannot be zero, otherwise the equation is not quadratic.
Frequently asked questions
What is the discriminant?
The value b squared minus 4ac. It tells you how many real roots exist.
What if there are no real roots?
The tool reports that the equation has no real solutions.
Can a be zero?
No, then it would be a linear equation.