x2 + 7x + 19
$$If \qquad x^2+7x+19=0 \mbox{ which it doesn't - then}\\\\
x=\frac{-7\pm \sqrt{49-76}}{2}\\\\
x=\frac{-7\pm(\sqrt{17})i}{2}\\\\$$
SO
$$x^2+7x+19=\left(x+\frac{7+(\sqrt{17})i}{2}\right)
\left(x+\frac{7-(\sqrt{17})i}{2}\right)$$
I think that is ok.