The expression given to us is:
This can be rewritten as:
Now, let us take as the common factor in the first two terms in the numerator and 5 as the common factor in the last two terms in the numerator. Thus, we get:
Now, taking as the common factor, we get:
The above is the simplest form of the given expression,
As we know that the denominator of a rational expression can never be zero, thus the only restriction in our case will be:
or, (subtracting 3 from both sides)
Thus, the restriction is that cannot be equal to .