What is the expression used to calculate the discriminant in the quadratic formula?

The discriminant in the quadratic formula is calculated using the expression ( b^2 - 4ac ). This expression is vital as it determines the nature of the roots of a quadratic equation represented in standard form as ( ax^2 + bx + c = 0 ).

The value of the discriminant reveals important information:

• If the discriminant is positive, there are two distinct real roots.

• If the discriminant is zero, there is exactly one real root (or a repeated root).

• If the discriminant is negative, there are no real roots, but instead, there are two complex roots.

Understanding the discriminant is crucial for solving quadratic equations and analyzing their graphs, helping students gain insights into the behavior of quadratic functions. The other expressions listed do not represent the discriminant and therefore do not provide the correct analysis of the roots in relation to a quadratic equation.