Primitive of Reciprocal of x by a x squared plus b x plus c

Theorem
Let $a \in \R_{\ne 0}$.

Then:
 * $\displaystyle \int \frac {\mathrm d x} {x \left({a x^2 + b x + c}\right)} = \frac 1 {2 c} \ln \left\vert{\frac {x^2} {a x^2 + b x + c} }\right\vert - \frac b {2 c} \int \frac {\mathrm d x} {a x^2 + b x + c}$