# How do you solve the equation 2x^2+8x+4=x^2+4x by completing the square?

Feb 16, 2017

The equation has one root $x = - 2$

#### Explanation:

First simplify the equation into a standard form
$2 {x}^{2} + 8 x + 4 = {x}^{2} + 4 x$
becomes
${x}^{2} + 4 x + 4 = 0$ (equation 2)

Use the formula
$\frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$

substitute in the values from equation 2
$\frac{- 4 \pm \sqrt{16 - 16}}{2}$

The equation has one root $x = - 2$