When should I use the quadratic formula?

If you're asked to solve a quadratic equation, you could factorise it, or you could use the quadratic formula. The quickest way is to factorise, but sometimes the numbers are too tricky to factorise, (if an exam question asks for the answer in decimal places, this is a good indication you will need this method) so in these situations we use the quadratic formula:

x= (-b+/-sqrt(b2-4ac))/2a

given the equation ax​2​+bx+c=0

You can then substitute the numbers from your equation into the formula, and you will get two values of x (remeber to do both + and - the square root) just like you would if you were to factorise the equation. 

Answered by Sarah M. Maths tutor

2814 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do i solve the quadratic x^2 + 5x + 6 = 0 ?


Express x^2+8x+15 in the form (x+a)^2-b


£3000 is invested for 2 years at 3.8% per annum compound interest. What is the total interest earned over the 2 years?


A house increases by 25% to £80,000. Find what it was worth before the rise.


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