How do I solve a quadratic equation?

All quadratic equations can be written in the form ax2 + bx + c = 0, where a, b and c are constants. Firstly, check whether you can easily factorise the equation into the form (x + p)(x + q) = 0, where pq = c and p + q = b. If you can do this, then the roots of the quadratic equation are -p and -q. 

If the equation does not factorise nicely, then the quadratic formula can be used to find the roots of the equation. Again, write the equation in form ax2 + bx + c = 0. Then the quadratic formula is given by x = (-b +/- sqrt(b2 - 4ac))/2a. This will give us two roots to the equation if b2 - 4ac > 0, one root to the equation if b2 - 4ac = 0 and no roots if b2 - 4ac < 0. Use a calculator to find the value of the root(s).

MS
Answered by Matthew S. Maths tutor

3907 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

James wins the lottery and gets £200,000. He decides to spend 10% of his winnings and invest the rest. From the money he has invested, he receives interest of 3% per year. How much money does James have after 5 years (to the nearest pound)?


x^2 - 10x + 21 = 0


A circular ice rink has a diameter of 60 meters. Calculate the area of the ice rink in terms of π in meters


What does it mean to "complete the square"?


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