The closed$-$loop transfer function of a system is

$T(s)=\frac{s^3+2s^2+3s+18}{s^5+2s^4+8s^3+16s^2-9s-18}$

Determine how many closed$-$loop poles lie in the right half$-$plane, in the left half$-$plane, and on the $j-$axis.

$2.$ How many poles are in the right half$-$plane, the left half$-$plane, and on the $j-$axis for the closedloop system shown as follows?

$T(s)=\frac{10}{s^6-2s^5-3s^4+s^2-2s-3}$

Consider the unity feedback system of the following figure with $G(s)=\frac{4}{s^2(s^2+4)}.$

Using the Routh$-$Hurwitz criterion, find the region of the $s-$plane where the poles of the closedloop system are located