If the general solution of the differential equation
\[
\frac{dy}{dx}
+
\frac{2x+2y-1}{x+y-5}
=
0
\]
is
\[
ax+by-9\log(x+y+p)=c,
\]
and \(b,a,p\) are in G.P., then the common ratio of this G.P. is
Show Hint
For equations involving
\[
x+y,
\]
use the substitution
\[
\boxed{z=x+y},
\]
so that
\[
\boxed{\frac{dz}{dx}=1+\frac{dy}{dx}},
\]
which usually converts the equation into a separable form.