The Discriminant Worksheets - Math Worksheets Center The discriminant in math is a parameter of a gadget or method evaluated as a service to its order or resolution. For quadratic equation that is: => ax 2 + bx + c = 0. The discriminant is: => b 2 - 4ac. For a cubic equation: => x 3 + ax 2 + bx + c = 0. The discriminant is: => a 2 b 2 + 18abc - 4b 3 - 4a 3c - 27c 2 The origins of a quadratic or ...