Answer:
The simplified form is  .
.
 is the excluded value for the given expression.
 is the excluded value for the given expression.
Step-by-step explanation:
Given:
The expression given is:

Let us simplify the numerator and denominator separately. 
The numerator is given as 
2 is a common factor in all the three terms. So, we factor it out. This gives,

Now, 
Therefore, the numerator becomes 
The denominator is given as: 
Factoring out 3, we get

Now,  is of the form
 is of the form 
So, 
Therefore, the denominator becomes 
Now, the given expression is simplified to:

There is  in the numerator and denominator. We can cancel them only if
 in the numerator and denominator. We can cancel them only if  as for
 as for  , the given expression is undefined.
, the given expression is undefined.
Now, cancelling the like terms considering  , we get:
, we get:

Therefore, the simplified form is 
The simplification is true only if   . So,
. So,  is the excluded value for the given expression.
 is the excluded value for the given expression.