Given,
The total energy of the particle, E=-100 J
The potential energy of the particle when it is at x=8.00 cm, P=-600 J
From the graph, the potential energy of the particle when it is at x=2.00 cm, P₀=-200 J
From the law of the conservation of energy, the total energy of the system always remains constant. But the form of the energy may change.
The total mechanical energy is the sum of potential and kinetic energy.
Thus the total energy of the particle is always -100 J
Hence, its total energy when it is at x=2.00 cm is also -100 J