Primitive of Reciprocal of x by a x + b cubed

Theorem

 * $\displaystyle \int \frac {\mathrm d x} {x \left({a x + b}\right)^3} = \frac {a^2 x^2} {2 b^3 \left({a x + b}\right)^2} - \frac {2 a x} {b^3 \left({a x + b}\right)} + \frac 1 {b^3} \ln \left\vert{\frac x {a x + b} }\right\vert + C$