Verify the property: 
by taking:
(i) 
(ii) 
(iii) 
(iv) 
(i) We have,
x * y = 
* (
)
= 
y * x = 
* (
)
= 
(ii) We have,
x * y = 
* (
)
= 
y * x = 
* (
)
= 
(iii) We have,
x * y = 2 * (
)
= 
= 
y * x = 
* 2
= 
= 
(iv) We have,
x * y = 0 * (
)
= 0
y * x = 
* 0
= 0
1