Discriminant
GMAT glossary · Quantitative Reasoning
Definition
The expression b^2-4ac that determines the nature of a quadratic equation’s solutions: positive → two real roots, zero → one repeated real root, negative → no real roots.
Discriminant in plain English
The discriminant is a one-shot check that tells you what KIND of answers a quadratic equation has, before you fully solve it. You compute b^2 - 4ac from the equation, and its sign is the whole message: positive means two different real answers, zero means one repeated answer, and negative means no real answers at all (the curve never touches the x-axis). It's like peeking at the recipe to know how many servings you'll get without cooking the whole meal, a fast way to predict the outcome.
Sign up free: all 257 GMAT terms as flashcards, plus practice questions with full explanations →
Related GMAT terms
GMAT practice questions · GMAT flashcards · GMAT study guide