Answer
$\displaystyle \frac{2x-1}{x^{2}-x}$
Work Step by Step
(see p. 838, Generalized Rule)$\quad$
$\displaystyle \frac{d}{dx}[\ln|u|]=\frac{1}{u}\cdot\frac{du}{dx}$
$u(x)=x^{2}-x$
$\displaystyle \frac{du}{dx}=2x-1$
$\displaystyle \frac{d}{dx}[\ln|2x^{2}+1|]=\frac{1}{x^{2}-x}\cdot(2x-1)$
$=\displaystyle \frac{2x-1}{x^{2}-x}$