how to show that
$\displaystyle \frac{6}{(s^2+2s+2))^2}= \[\frac{6}{{s}^{2}+2\,s+2}\] -3 \[\frac{\left( s+1\right) \,\left( 2\,s+2\right) }{{\left( {s}^{2}+2\,s+2\right) }^{2}}\] $
In order to get a common denominator, you will need to multiply both numerator and denominator of the first fraction on the right side by $\displaystyle s^2+ 2s+ 2$.