Find the complete integral of the partial differential equation $(p^2 + q^2)x = pz$ and deduce the solution which passes through the curve $x = 0, z^2 = 4y$.
I am able to find the complete solution which is : $z^2=a^2x^2+(ay+b)^2$ where $a$ and $b$ are some arbitrary constant. But I am not able to find the particular solution. Finding particular solution will require eliminating $a$ and $b$ but I am still getting one of the constant in my solution.