1. Identity of ring and zero of ring Theorem 6.27: Let (R; + " l be a ring. Then the following results hold (1)a*0=0*a=0 for va∈R (2)a*(-bF(-a)*b--(a b)for v a, bER ◆(3)(-a)*(-b)= a*b for va,b∈R Let I be identity about*. Then ◆(4)(-1)*a= a for va∈R ◆(5)(-1)*(-1)=1 1. Identity of ring and zero of ring  Theorem 6.27: Let [R;+,*] be a ring. Then the following results hold.  (1)a*0=0*a=0 for aR  (2)a*(-b)=(-a)*b=-(a*b)for a,bR  (3)(-a)*(-b)=a*b for a,bR  Let 1 be identity about * . Then  (4)(-1)*a=-a for aR  (5)(-1)*(-1)=1