2nd order PDE charcteristics... help please! :S

hi all, sorry again for the thousands of stupid questions! :P but heres another one...

http://img88.imageshack.us/img88/3209/picture13df1.png

ok i said for part (a) that the PDE is a hyperbolic type and so has two sets of real characteristics. and that the characteristics are http://img100.imageshack.us/img100/7...cture14dj6.png

then for part (b) i used the coordinates:

http://img86.imageshack.us/img86/5987/picture15ct2.png

which leads to the equation:

http://img301.imageshack.us/img301/5...cture16yi2.png

but then i am stuck... how can i get the 'general solution' from this, i think i am heading in the right direction, but i am not sure.

any help would be greatly appreciated!

thanks

Sarah :)