Solution The matrix A has 2 columns which is equal to the number of rows of B Hence AB is defined Now
6(2)
9(7)
6(6)
9(9)
6(0)
9(8)
AB
2(2)
3(7)
2(6)
3(9)
2(0)
3(8)
+
+
+


= 

+
+
+


=
12
63
36
81
0
72
4
21
12
27
0
24
+
+
+




+
+
+


 = 
75
117
72
25
39
24






Rationalised 2023-24
MATRICES         53
Remark  If AB is defined, then BA need not be defined In the above example, AB is
defined but BA is not defined because B has 3 column while A has only 2 (and not 3)
rows