MA18-03 Maths Coming soon
Solving a Quadratic Inequality
MA18-03
This lesson is coming soon.
In this lesson
Solve a quadratic inequality by finding its critical values and combining them into one correctly structured inequality statement, using set notation and a number line.
What it covers
- Finding the critical values of a quadratic inequality by factorising (or from a graph)
- Using a quick sketch of the parabola to decide whether the solution lies 'between' the critical values or 'outside' them
- Combining the two critical values into one correctly structured inequality statement (e.g. -a < x < a, or x < -a or x > a) rather than stopping at the two numbers
- Writing the solution using set notation and on a number line
Key words
For: AQA GCSE 8300, Edexcel GCSE 1MA1, Eduqas GCSE C300, Edexcel IGCSE 4MA1, OCR GCSE J560
On the specification
| Board | Spec | Statement |
|---|---|---|
| AQA GCSE 8300 | A22 | Solve linear inequalities in one variable |
| Edexcel GCSE 1MA1 | A22 | Solve linear inequalities in one variable; represent the solution set on a number line |
| Eduqas GCSE C300 | HA22 | Solve linear inequalities in one or two variable(s), and quadratic inequalities in one variable; represent the solution set on a number line, using set notation and on a graph |
| Edexcel IGCSE 4MA1 | H2.8A | Solve quadratic inequalities in one unknown and represent the solution set on a number line |
| OCR GCSE J560 | 6.04a | Understand and use the symbols <, ≤, > and ≥ |
For teachers
This GCSE Maths lesson teaches solving a quadratic inequality. By the end, students should be able to solve a quadratic inequality by finding its critical values and combining them into one correctly structured inequality statement, using set notation and a number line. It works through two worked examples and the mistakes examiners report.