Answer
See below
Work Step by Step
Since, $y(s)=-\dfrac{1}{s+1} +\dfrac{1}{s-2}-\dfrac{2}{(s+1)^2}$
The inverse Laplace transform of function can be expressed as:
$y(t)=L^{-1} [-\dfrac{1}{s+1} +\dfrac{1}{s-2}-\dfrac{2}{(s+1)^2}]$
Now, apply the first shifting Theorem.
$f(t)= -e^{-t} +e^{2t} -2te^{-t} $