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 ▸

What is the simplified version of ( 2a+4a^2+3a)


Which of these fractions is the largest - 33/56 ,4/7, 9/21, 6/14


Expand and simplify: (x+7)(x+3)


Tom's dad is 3 times older than him. In 15 years the sum of Tom's and his dad's ages will be equal to 102. How old are Tom and his dad now?


We're here to help

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