GCSE Maths: Quadratics
Master GCSE Maths quadratics — factorising, completing the square, the quadratic formula and sketching parabolas. AQA, Edexcel, OCR and Eduqas.
AlgebraFoundation & HigherAQA · Edexcel · OCR · Eduqas
What you need to know
The concepts examiners test on quadratics, and what each one is really asking.
Factorising quadratics
Completing the square
Quadratic formula
Sketching quadratic graphs
Solving quadratic equations
Where marks get lost
The exam technique that separates a correct method from a correct answer.
- Try factorising first — it is quickest if it works
- Use the quadratic formula when the equation does not factorise
- For completing the square: (x + b/2)² - (b/2)² + c
Quadratics questions students ask
When should I use the quadratic formula?
Use the quadratic formula x = (−b ± √(b²−4ac)) / 2a when a quadratic equation cannot be factorised, or when decimal answers are required.
What is the discriminant?
The discriminant is b²−4ac. If it is positive, there are 2 real roots; if zero, 1 repeated root; if negative, no real roots.