
Solution:
Given expression:

To simplify the given expression:

Let us first solve the numerator of the expression
.
To add or subtract the fraction, the denominators of the fraction must be same.
To make it same, multiply
by
and
by
.

------------------- (1)
Now, solve the denominator of the expression
.
To add or subtract the fraction, the denominators of the fraction must be same.
To make it same, multiply
by
and
by
.

------------------- (2)
Substitute (1) and (2) in the given expression.

Using rational rule: 

Common factor ab get canceled.

Hence the simplified expression is
.