I would the answer to x is 12
The third one is the smallest

Solution:
Given expression is
.
To simplify the expression 
Let us first convert the mixed fraction into improper fraction.



Take LCM for the denominators (LCM of 4, 8 = 8) and make the same.



Now, divide 51 by 8 and again write it in the mixed fraction.


Hence, the simplified answer is
.