I have to solve the trinomial $2x^2+4x+1 = 0$, which should equal $-1 \pm \frac{1}{2}\sqrt{2}$

So far, my steps are:

$$2x^2+4x=-1$$

$$2(x^2+2x)=-1$$

$$x^2+2x=\frac{-1}{2}$$

This is where I get stuck. I can take $\frac{-1}{2}$ to the left side, but it's still unfactorable.

*How can I solve this equation?*