Algebra 1 · Quadratic Functions

Discriminant

Algebra 1 · Quadratic Functions

Definition

The discriminant is the value b^2 - 4ac that tells the number and type of solutions to a quadratic.

Examples

  • If b^2 - 4ac > 0, there are two real solutions.
  • If b^2 - 4ac < 0, there are no real solutions.

Key rule

The sign of the discriminant reveals the solution count.

Memory hook

Discriminant = b^2 - 4ac decides how many roots.