Hi I'm stuck with a problem, I'm fine with differentials but the way this is worded confuses me!

Valuation of a storage facility gives equation:

V'' - rV = cP where c and r are constants

V: R->R is a function of the variable P and it wants me to find the general solution V (P).

I'm going round in circles here, if V is a function of P then am I right in saying V'' = d^2V/dP^2 ??

but then where do I go, do they want V = P something?

please help!