Primitive of Reciprocal of a x + b by p x + q

Theorem

 * $\ds \int \frac {\d x} {\paren {a x + b} \paren {p x + q} } = \frac 1 {b p - a q} \ln \size {\frac {p x + q} {a x + b} } + C$

where $b p \ne a q$.