1. 

   Sacha New Member

   (3b-1)(3b+1)-(b-5)(b+5)

    

   Sacha, 21 янв 2010

   #1
2. 

   Matsievskaya Olga New Member

   (9b^2-1) - (b^2-25)=8b^2+24=8(b^2+3)

    

   Matsievskaya Olga, 21 янв 2010

   #2