TeX source:

\begin{aligned}x &=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a} \\&=\frac{-4 \pm \sqrt{4^{2}-4(2)(-4)}}{2(2)} \\&=\frac{-4 \pm \sqrt{48}}{4} \\&=\frac{-4 \pm \sqrt{3(16)}}{4} \\&=-1 \pm \sqrt{3}\end{aligned}