For the below system set up a set of state variable equations, and then solve using Laplace transformations.
For the upper mass:
m 1 = 80 k g {\displaystyle m_{1}=80kg{\frac {}{}}}
k 1 = 60000 N m {\displaystyle k_{1}=60000{\frac {N}{m}}}
b 1 = 0.1 {\displaystyle b_{1}=0.1{\frac {}{}}}
And for the lower mass:
m 2 = 400 k g {\displaystyle m_{2}=400kg{\frac {}{}}}
k 2 = 120000 N m {\displaystyle k_{2}=120000{\frac {N}{m}}}
b 2 = 0.2 {\displaystyle b_{2}=0.2{\frac {}{}}}