Let A = 
1
2
1
2
3
1
1
1
5
�
�







 Verify that
(i) [adj A]–1 = adj (A–1)
(ii) (A–1)–1 = A
5 Evaluate 
x
y
x
y
y
x
y
x
x
y
x
y
+
+
+
6 Evaluate 
1
1
1
x
y
x
y
y
x
x+ y
+
Rationalised 2023-24
 100
MATHEMATICS
Using properties  of determinants in Exercises 11 to 15, prove that:
7