Work energy principle

Is the work energy principle, the total change in energy = total work done on particle

or

Total change in energy = workdone by resistive forces on particle?

How would you apply work energy principle to these situations?

In these situations it can help to look at things at the begining and at the end.

Try writing down the energy the particle has at each point.

For example, at the point A, what are the values of

1) Kinetic energy $\dfrac{1}{2}mv^2$

2) Gravitational potential $mg \Delta h$

3) Work done overcoming the frictional forces $\mu Rd$

4) Elastic potential energy, although if this is M2 then it's unlikely to come up, $\dfrac{\lambda x^2}{l}$

To answer your initial question, though, what you said first is correct.