Y bus matrix after removing node four   
 
  - 8.4111111i    1.3888889i    6.2222222i  
    1.3888889i  - 6.9111111i    4.7222222i  
    6.2222222i    4.7222222i  - 10.944444i  
 
 Y bus matrix after removing node three   
 
  - 4.8736041i    4.0736041i  
    4.0736041i  - 4.8736041i