E$7\mathrm{.}5$ Consider a unity feedback system with a loop trans$-$

fer function

L$1$s$2=$ G c$1$s$2$G$1$s$2=1$

s$3+50$s$2+500$s $+1000.$

$($a$)$ Find the breakaway point on the real axis. $($b$)$ Find

the asymptote centroid. $($c$)$ Find the value of K at the

breakaway point.