I already got Q(s)=150/(s(s^2+20s+200)), then i complete the square on the quadratic.
I got Q(s)=150/(s((s+10)^2+10^2))). But then i cant find the Q(t) because the equation (s+10)^2+10^2=0 dosent have roots. Or i have to use complex numbers ? So I am confused.