\[
\boxed{
 \left\{ {\frac {\rm d}{{\rm d}t}}x \left( t \right) =ax \left( t \right) +gy \left( t \right) +\beta\,z \left( t \right) ,{\frac {\rm d}{{\rm d}t}}y \left( t \right) =gx \left( t \right) +by \left( t \right) +\alpha\,z \left( t \right) ,{\frac {\rm d}{{\rm d}t}}z \left( t \right) =\beta\,x \left( t \right) +\alpha\,y \left( t \right) +cz \left( t \right)  \right\} }
\]