A feedbackk control system has the transfer function

A feedbackk control system has the transfer function
A feedback control system has the transfer function
G(s)/1+G(s),where G(s)=s+4/s(square)-1
and s represent the frequency domain
1.show that the system is stable
2.find the impulse response h(t) of the system
d(square)x/dt(square)+5*dx/dt+4x=F(t)
3.state,with reasons,whether this system is stable