The second equation should be
X ( s ) = 80 ( s 2 + 2 s + 4 ) ( s + 20 ) ( 1 s ) . {\displaystyle X(s)={\frac {80}{\left(s^{2}+2s+4\right)\left(s+20\right)}}\left({\frac {1}{s}}\right).}
Return to errata.