  A method for finding the general solution to the partial differential
equations: \ $F(u_x,u_y)=0$; \ $F(f(x)\:u_x,u_y)=0$ \ (or \
$F(u_x,h(y)\:u_y)=0$) \ is presented, founded on a Legendre like transformation
and a theorem for Pfaffian differential forms. As the solution obtained depends
on an arbitrary function, then it is a general solution. As an extension of the
method it is obtained a general solution to PDE: \ $F(f(x)\:u_x,u_y)=G(x)$, and
then applied to unidimensional Hamilton-Jacobi equation.
