$$-[x]=\frac{3}{2^{2}(s+1)(s+4)}-\frac{1}{s(s+1)}$$
$x=\frac{s+16}{4s\left(s+1\right)\left(s+4\right)}$
$s\neq -4\text{ and }s\neq -1\text{ and }s\neq 0$