Answer: (a)

(b)

(c)

(d)

Explanation:
Properties of exponents :
1)

2)

3)

4)

Now , we simplify the given expression using the above properties.
a)

[By property (1)]
[∵ (+)(-)=(-)]
b)

[By property (3)]
[∵ (-)(-)=(+)]
c)

[By property (2)]
[By property (4)]
d)

[By property (3)]