## FANDOM

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Completing the square is one of the three methods (quadratic factorisation and the quadratic formula being the other two) used to solve a quadratic equation, such as $x^2 + 4x + 4$.

The Aim: to write the equation in the form

$(x+a)^2 = b$

## ExampleEdit

$x^2 + 10x = 52$

First fill in with half of the 10 $(x+5)^2$

Expand the brackets

$x^2 + 10x + 25 = 52 + 25$i belive that at the bottom, it should be -3..77 .

$(x+5)^2 = 77$

$x + 5 = \pm \sqrt{77}$

$x = \pm \sqrt{77} - 5$

$x = 3.77 or -13.8 (3s.f.)$