Discriminant Practice Test
20 varied discriminant questions with worked explanations.
Calculate D=b²-4ac and use its sign and square status to classify quadratic roots and graph intersections.
20 varied discriminant questions with worked explanations.
For ax²+bx+c=0, the discriminant D=b²-4ac determines whether the quadratic has two real roots, one repeated real root, or no real roots. When D is positive, its square status also distinguishes rational roots from irrational roots for rational coefficients.
This test combines numerical calculation with interpretation. Questions ask for D, √D, root counts, x-intercepts, repeated-root formulas, classifications, and discriminants after an equation has first been rearranged into standard form.
You will identify coefficients including zero or negative values, calculate D accurately, interpret positive, zero, and negative cases, distinguish perfect-square and nonsquare positive values, connect roots with x-intercepts, and use D inside the quadratic formula.
Common errors include using b instead of b², losing the sign of a negative c, forgetting the factor 4, reading coefficients before moving all terms to one side, claiming every positive D gives rational roots, and confusing D with √D.
Use this free 20-question test for Algebra 1, Algebra 2, quadratic review, ACT-style preparation, tutoring, or independent study.