Answer:
1)
is not an odd function
2)
is an odd function
3)
is not an odd function
Step-by-step explanation:
The function is odd, which satisfies the condition f(-x) = - f(x)
first we check for 
Replace x with - x,


we can't write this in the form of f(-x) = - f(x)
so, this is not an odd function
check for 
Replace x with - x,



so, this is an odd function
check for 
Replace x with - x,


we can't write this in the form of f(-x) = - f(x)
so, this is not an odd function