Fable range of gains using matlab plot bode

Question

Block diagram of the system:

Where τ₁ = 3, τ₂ = 1

Open Loop Transfer Function = K / {s(τ₁s + 1) (τ₂s + 1)}

Closed Loop Transfer Function =  {K(τ₂s + 1)} / {K + s(τ₁s + 1) (τ₂s + 1)} = {K(τ₂s + 1)} / {τ₁τ₂s² + (τ₁ + τ₂)s + K + 1)}

a) Find the stable range of gains

b) Using MATLAB, plot:

1. Bode plot (gain margin, phase margin)
2. Nyquist plot (gain margin, phase margin)
3. Root Locus.