A system function is H ( s ) = V ( s )I ( s ) = ss + 3, the system is at rest for t 0 is given by

A system function is $$H\left(s\right)=\frac{V\left(s\right)}{I\left(s\right)}=\frac{s}{s+3},$$     the system is at rest for t < 0. i(t) = 2u(t) is an unit step. v(t) for t > 0 is given by