How do you use the quadratic formula?

The equation for the quadratic formula is x = (-b +/- √(b^2 - 4ac))/2a for when the equation ax^2 + bx + c is equal to 0. When you have the equation ax^2 + bx + c, where a, b and c are given numbers, you can sub the numbers into the quadratic formula to find x.For example, you are given 2x^2 + 6x + 4 = 0 and asked to find x. Here you can see that a=2 , b=6 and c=4. You can then sub these into the quadratic formula to give x = (-6 +/- √(6^2 - 4(2)(4)))/2(2) and put this into your calculator to find that x = -2 or -1.

IB
Answered by Isla B. Maths tutor

2388 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Find the inverse of the following function: g(x) = 4/(3-x)


Expand the following : (2x+3)(x-1)


For what values of x is 2x^2 - 11x - 6 > 0 ?


Simultaneous equations - Find the values of y and x: 3


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