How this calculation works
A positive leading coefficient puts the negative region between two real roots. A negative leading coefficient reverses that pattern.
THE FORMULA
Locate real roots and test the sign between rootsA worked example
x²−5x+6 is negative strictly between 2 and 3.
Good to know
Enter a nonzero quadratic coefficient.
Reference: OpenStax Algebra and Trigonometry (opens in a new tab) ↗
Read the result
Solve a strict quadratic inequality for the real x where ax²+bx+c is negative.
The primary result is labeled “Solution for f(x) < 0”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
Enter a nonzero quadratic coefficient.
For a related exercise, try the quadratic equation solver.
A few questions, answered
How can I check the default inputs by hand?
x²−5x+6 is negative strictly between 2 and 3.
Which rule does this calculator apply?
Locate real roots and test the sign between roots