Some properties (AB)C=A(BC) ⊙入(4B)=入4B=4AB OA(B+C)=AB+AC 8+一- Renmrk 7.11 Note: In general, 4B=4C,4≠0中B=C Tongji University】 7/14Some properties .1 (AB)C = A(BC) .2 λ(AB) = (λA)B = A(λB) 3. A(B + C) = AB + AC (B + C)A = BA + CA . Remark 7.1.1 . . ( 0 0 a 0 ) ( 1 1 1 1 ) ̸= ( 1 1 1 1 ) ( 0 0 a 0 ) Note: In general, AB = AC, A ̸= 0 ; B = C. A ̸= O , AB = O ; B = O. A ̸= O , B ̸= O ; AB ̸= O. (Tongji University) Linear Algebra 7 / 14