Answer:
The system's potential energy is

Step-by-step explanation:
The total mechanical energy of the system is E which the sum of the potential energy and the kinetic energy.
The total energy of a simple harmonic oscillator is given as E =
.
The system's kinetic energy is given as

Total system Energy (E) = Potential Energy (P) + Kinetic Energy (K)
E = P+K
P = E - K
P =

P =
=

Potential Energy (P) of the system =