Example 15 Find AB, if 
0
1
A
0
−2


= 



 and 
3
5
B
0
0


= 


 Solution We have 
0
1
3
5
0
0
AB
0
2
0
0
0
0
−

 



=
=

 




 


 Thus, if the product of two matrices is a zero matrix, it is not necessary that one of
the matrices is a zero matrix 3