Urgent help- Determining the inverse discrete time Fourier transform

hey guys,

I need someone to help me with this problem ASAP!
attached please find the pictures.it looks lyk an easy partial fraction question but im not able to do it.i have also shown the method in which i have tried out but im unable to reach to the correct ans.

if anyone could tell me HOW TO GET 'STEP 1' (as marked on the picture).

please help!