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

How would you solve  x2+8x+16=81Show that this can be factorised (x+4)2=92Which can then be easily solved by square rooting both sides
What if we could now use this method to solve all quadratics?!!?
Consider Solve  x2+6x+1=0
We can complete the square by:(x+3)2-9+1=0 (x+3)2-8=0 (x+3)2=8 (x+3)=±√8 x=-3±2√2

Related Maths GCSE answers

All answers ▸

Solve the simultaneous equations: 3x + y = 19 and x - 2y = -3


Factorise 2e – 4f + ex -2fx


How do I work out how a number is written in fraction form, if it is a reoccurring decimal?


Many students do not understand the rules for when one can 'cancel' in regards to fractions


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