The discriminate formula is b squared minus four ac for quadratic equation in standard form ax squared plus bx plus c. Math Example--Quadratics--Calculating the Discriminant: Example 6.Draw graphs of quadratic functions. The discriminant of a quadratic equation is the value b2 - 4ac. Solve and graph mathematical and real-world problems that are modeled with quadratic functions. The formula for the Discriminant. This is part of a collection of math formulas. The discriminant of a quadratic equation helps you to determine the nature of the solutions. Step 1: Identify a, b, and c in the quadratic equation. Step 2: Substitute the values from step 1 into the quadratic formula.