Expression for displacement x as a function t.?

Question

In a frictionless system of a block of mass m = 2kg attached to a spring of spring constant k = 8 N/m, the mass is displaced from the equilibrium position by x = 3m and let go with zero initial velocity, v(initial) = 0 m/s.

Answer this question :
Write an expression for the displacement x of the mass from equilibrium as a function of time. Use numerical values wherever possible.

I've figured out the answer already so if anyone wants to take a crack at it; i'll give the best answer to the right answers or closest answer.

Answer 1

This should have already been covered in your class as a harmonic oscillator.

The general solution is a cosine function.

Figure out the potential energy stored in the spring; this must conserved and represents the maximum kinetic energy of the mass as it passes the zero displacement point.

Answer 2

x = the comfudermunt of n+t squiddled to f412, yobtoppled to nty and blendered to make a very strong but fine sushu.

I DON'T HAVE A CLUE WHAT YOU'RE (OR I'M) TAKING ABOUT! :p