# How do you solve 2x² + 8x + 5 = 0 by completing the square?

Jul 21, 2017

$x = - 2 \pm \frac{\sqrt{3}}{\sqrt{2}}$

#### Explanation:

$2 {x}^{2} + 8 x = - 5$
Divide both sides by 2
${x}^{2} + 4 x = - \frac{5}{2}$
${x}^{2} + 4 x + 4 = 4 - \frac{5}{2} = \frac{3}{2}$.
${\left(x + 2\right)}^{2} = \frac{3}{2}$
$x + 2 = \pm \frac{\sqrt{3}}{\sqrt{2}}$.

$x = - 2 \pm \frac{\sqrt{3}}{\sqrt{2}}$.