Just re-learning the quadratic equation.

I understand it until the end where the example in my book shows when solving:

$\displaystyle x= \dfrac {-4\pm2\sqrt{6}}{4}$

Then:

$\displaystyle x= -1- \dfrac {\sqrt{6}}{2}$ or, $\displaystyle x=-1+\dfrac {\sqrt{6}}{2}$

Not quite sure how they factored, it does not explain. I tried, but kept coming up with.

$\displaystyle x= -2 \pm \dfrac {\sqrt{6}}{2}$

Somebody care to explain how it's done properly..