Thank you. That’s what I thought, since the Newton ‘prime’ notation implies derivatives of time.
It would also be nice to know if ‘x’ is a function of time (or anything else) or is simply a value. If it is a funciton of time, integrating the differential equation symbolically may not be possible (at least in a closed form, since the RHS would have to be integrated separately, then substituted back into the integrated LHS). That would slightly complicate things.
With what I currently know about this, it can just be plugged into the demonstration code I cited to in my original Answer to produce —