For a mass$-$spring$-$damper system the governing equation is:

$m{x}^{}+c{x}^{}+kx=0$

$m=7kg$

$c=4N^{**}\frac{s}{m}$

$k=75\frac{N}{m}$

Determine the position, using $x.$ format, at $t=7sec$ if the system starts from $x(0)=x_o=0\mathrm{.}5m$ with an initial velocity of $-0\mathrm{.}1\frac{m}{s}$