Discriminant Test (Quadratics) [IB Math AA SL/HL]

The speaker explains the discriminant test for quadratic equations, defining the discriminant as b² - 4ac. They illustrate its application with three examples, demonstrating how a positive discriminant indicates two distinct real roots, a zero discriminant indicates one real root (or two equal roots), and a negative discriminant indicates no real roots. The speaker also notes that in IB Math exams, students might need to work backward from given information about the number of roots to solve for unknown variables within the quadratic equation.