Solve x^2 + 4x + 4 = 0

To solve this equation we have two different methods:

1) We can solve this method 'by hand' and is done by knowing how to factorise the quadratic and is done by looking at the equation given to us to find hints that will help solve it.

(x " first symbol " a) (x " second symbol" b) = 0

WIthout going too in depth:

the second symbol "+" tells us that the two symbols in our answer are the same

the first symbol "+" combined with the knowledge of second symbol "+" tells us that the two symbols in our answer are both "+"

next we know "a" times "b" = 4 and "a" + "b" = 4 so we find numbers that match this description e.g. 2 and 2 and so we have found our answer

x^2 + 4x + 4 = 0 = (x+2)(x+2) 

and so x = -2 

2) Using the quadratic formula:

 (-b +- sqrt(b^2 - 4ac))/2

This method is simpler and requires you to only plug in the numbers in the correct place of the formula, the a, b and c from the formula come from the general equation: ax^2 + bx + c which all quadratic formulas can be related to. 

e.g.) ax^2 + bx + c and so a = 1, b = 4 c = 4 in our example

and our result is -2

KH
Answered by King Him C. Maths tutor

4261 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

What is the size of the interior angle of a regular 12-sided polygon?


Find the values of k for which the equation (2k-3)x^2- kx+(k-1)=0 has equal roots.


How do I find the length of a side of a triangle using the cosine rule?


Solve the following simultaneous equations: (1) 4x+y=7 and (2) 3x+2y=9


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