Paper 1 · Functions and Graphs
⏱ Tested in 4 exam questions since 2016
Lesson 3 of 10
Functions and Graphs 3 – Vertex form/Completing the square
This tutorial is for members
Read the lesson notes free below — subscribe to watch the full worked video and download the PDF.
Subscribe for full access · €199/yrYou’ll learn
- Complete the square to write ax² + bx + c in vertex form a(x − h)² + k
- Use the half-and-square, add-and-subtract trick to build the perfect square
- Factor out (never divide by) a leading coefficient, including negative ones
- Hence read off the turning point and say whether it's a maximum or minimum
Most recent exam questions
- 2025 P1 Q5(a)
- 2021 P1 Q5(a)(i)
- 2017 P1 Q1(a)
- 2017 P1 Q1(b)
- 2017 P1 Q1(c)(ii)
💬 Stuck on something in this lesson?
Send your question with this lesson’s name attached — you’ll get a reply by email.