How do I find the root of a quadratic equation?

Usually the easiest way to find the root of a quadratic is to factorise it so you have something a form similar to - (x+2)(x-1)=0.

From here you need to find a value for x that makes each bracket equal to zero. Here we can see our answers are x = 1 and x = -2.

If the equation cannot be factorised our backup method that is slightly more complicated but always correct is to use the quadratic equation. 

This is given as x = (-b ± (b2-4ac)1/2)/2a,

Where a, b and c come from your original quadratic as ax2+bx+c. 

NF
Answered by Nicky F. Maths tutor

5857 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

I don't understand how functions work. How do I decide if something is a function?


Integrate ((7e^(x/2))/4) with respect to x within the bounds of x=0 and x=2. (Basic introduction to definite integration)


Find the intergal of 2x^5 -1/(4x^3) -5 giving each term in its simplest form.


f(x) = 2x3 – 5x2 + ax + 18 where a is a constant. Given that (x – 3) is a factor of f(x), (a) show that a = – 9 (2) (b) factorise f(x) completely. (4) Given that g(y) = 2(33y ) – 5(32y ) – 9(3y ) + 18 (c) find the values of y that satisfy g(y) = 0, givi


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning