Now
A11 = –1,
A12 = – 8,
A13 = –10
A21 = –5,
A22 = – 6,
A23 = 1
A31 = –1,
A32 = 9,
A33 = 7
Rationalised 2023-24
 96
MATHEMATICS
Therefore
A–1 =
1
5
1
1
8
6
9
17
10
1
7
−
−
−




−
−
−




−

So
X =
–1
1
5
1
8
1
A B =
8
6
9
1
17
10
1
7
4
−
−
−

  

  
−
−
−

  

  
−
  
i e x
y
z
 
 
 
 
 
 =
17
1
1
34
2
17
51
3
−

 


 
−
−
=


 


 
−

 
Hence
x = 1, y = 2 and z = 3 Example 18 The sum of three numbers is 6