This introduction covers Above or Below the Curve? within Quadratic Inequalities for GCSE Mathematics. Revise Quadratic Inequalities in Algebra for GCSE Mathematics with 10 exam-style questions and 2 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 1 of 5 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
Above or Below the Curve?
A parabola divides the x-axis into regions. Where is y > 0? Where is y < 0? Solving quadratic inequalities is about finding which x-values make the quadratic positive or negative.
Practice questions for Quadratic Inequalities
For a positive (U-shaped) parabola with roots at x = 2 and x = 5, the expression is negative (below the x-axis) for which values of x?
Explain what the solution set of x² + 2x + 5 > 0 is, justifying your answer using the discriminant.
Quick recall flashcards
Quadratic Inequalities
Sketch graph, identify where curve is above/below x-axis
Quadratic Inequality Pattern
For U-shape: > 0 = outside roots (x < a or x > b), < 0 = between roots (a < x < b)