How do I know how many roots a quadratic equation has?

Let ax2 + bx + c = 0 be the equation in question where a,b,c are real numbers with a not equal to 0 (otherwise we would not have a quadratic).

 

If:

b2 - 4ac > 0 then there are two (real) roots

b2 - 4ac = 0 then there is exactly one (real) root

b2 - 4ac < 0 then there are no (real) roots.

AG
Answered by Amit G. Maths tutor

9195 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

What's the difference between a histogram and a bar chart?


Work out the nth term of the sequence 3, 7, 11, 15, ...


How do you solve a quadratic equation? eg: x^2 + 2x - 8


Solve x^2 = 4(x – 3)^2


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:

© 2025 by IXL Learning