# How do you solve using completing the square method x^2+2x=9?

Mar 30, 2018

#### Answer:

$x = - 1 \pm \sqrt{10}$

#### Explanation:

${x}^{2} + 2 x = 9$
${x}^{2} + 2 x + 1 = 9 + 1$
${\left(x + 1\right)}^{2} = 10$
Take the square root of both sides:
$x + 1 = \pm \sqrt{10}$
The 2 real roots are:
$x 1 = - 1 + \sqrt{10}$
$x 2 = - 1 - \sqrt{10}$