Trouble with inverse Z-transform and calculating of samples I have a little problem. I have to solve this task but I can't. 


  Z-transform of sequence $\{x(k)\}$ describe by the formula:
  
  $$X(z) = \frac{2.5 -3.15z^{-1} + 1.2 z^{-2}}{1-2.3z^{-1} + 1.2z^{-2}}$$
  
  Calculate of samples $x(-2), x(-1), x(0), x(1)$ and $x(2)$
  double-sides sequence, which correspond this Z-transform.


Thank you very much.
The poles in the equation are Z=1.5,0.8;hence to be two sided the roc is $0.8&lt;=z&lt;=1.5$
so the 0.8 term is right sided and 1.5 term is left sided let us do partial fractions now $ X(Z)=1+\frac{1.5-0.85z^{-1}} {(1-0.8z^{-1})(1-1.5z^{-1})} $
after doing some maths i got $x(n)=\delta(n)-0.5(0.8)^nu(n)-2(1.5)^nu(-n-1)$
so x(-2)=-0.88888,x(-1)=-1.3333,x(0)=0.5,x(1)=-0.4,x(2)=-0.32.