Assume that the controller and the plant transter function are selected as $c=K\frac{(s+z)}{s+9}$ and $p=\frac{(s+6)}{(s^2+9)}$ respectively. Then

a$-)$ Using root locus design technique calculate the values of $K$ and $z$ in order closed loop system to have a pole at $s=-6+3J($no other meth$)$