# How do you solve x^2+8x=12 using the quadratic formula?

Jul 9, 2015

$x = \left\{- 4 + 2 \sqrt{7} , - 4 - 2 \sqrt{7}\right\}$

#### Explanation:

The equation is ${x}^{2} - 8 \cdot x - 12 = 0$
$x = \frac{- b \pm \sqrt{{b}^{2} - 4 \cdot a \cdot c}}{2 \cdot a}$
Here, a = 1, b = 8, c = -12
Substituting these values,

$x = \frac{- 8 \pm \sqrt{{\left(- 8\right)}^{2} + 48}}{2 \cdot 1} = \frac{- 8 \pm \sqrt{112}}{2} = - 4 \pm 2 \sqrt{7}$

Thus the answer is $x = \left\{- 4 + 2 \sqrt{7} , - 4 - 2 \sqrt{7}\right\}$