Part a   
 
 the overall voltage gain with 10 % negative feedback is   
 
  - 8.  
 
 Part b   
 
 the overall voltage gain with 20 % negative feedback is   
 
  - 4.4444444  
 
 Part c   
 
 the overall voltage gain with 1 % positive feedback is   
 
  - 66.666667