Author note — to cover

Solve quadratics already equal to zero by factorising and setting each bracket to zero, since a product vanishes only when a factor does. Foundation: monic x² + bx + c cases including the difference of two squares. Higher adds a > 1 via the harder factorising page; rearranging first is the Higher sibling. (A18)

• Fluency — direct questions on solving a quadratic by factorising, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).