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

Answered by Maths tutor

2909 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Make x the subject of 5(x-3) = y(4-3x)


Solve the simultaneous equations, 3x + 2y = 4 (1) 4x + 5y = 17 (2)


How do you substitute a number into an algebraic expression?


If the area of a sector of a circle is 3*pi cm^2 and the circle has a radius of 6cm, what is the angle of the sector?


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