How do you complete the square?

You start off with a formula in the form y = x2 + bx. The first step is to add the square of half of the coefficient of x: (b/2)2. This allows us to rearrange the formula into (x+ b/2)2 . However, our formula is not equal to what we started with since we added (b/2)2 so we have to subtract it from the end. If the formula you start with has a constant (a term without the variable x) you ignore it in order to rearrange the x2 +bx part and then add it back on at the end as it will combine with the (b/2)2 term we subtracted.

JM
Answered by Jamie M. Maths tutor

2479 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Could you please go through an example question where you have to solve quadratic simultaneous equations?


How do I solve a quadratic equation by completing the square?


The perimeter of a right angled triangle is 105cm. The lengths of its sides are in the ratio of 2:6:7. Work out the area of the triangle.


Factorise h^2 - 36.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences