3.26: Mid-point and perpendicular through $C$

The points $A$, $B$ and $C$ have coordinates $(2, 6)$, $(6, 1)$ and $(p, q)$ respectively. Given that $B$ is the mid-point of $AC$, find the equation of the line that passes through $C$ and is perpendicular to $AB$. Give your answer in the form $ax+by=c$, where $a$, $b$ and $c$ are integers.