Answer:
The missing exponent on the m-term is 2.
Explanation:
 Given : Polynomial 
 
 
We have to find the value of a so that when we fully simplified the given polynomial it has degree of 4. 
Consider the given polynomial 
 
 
Since, given when fully simplified the given polynomial it has degree of 4. 
Degree of the polynomial is the highest power of the variables and the sum of exponents that are together.
Since , before simplifying the degree of given polynomial 
 has degree 5 (
 has degree 5 ( 
 =2 +3 = 5 )
 =2 +3 = 5 ) 
So , In order to become the polynomial in degree 4 .
The total degree of 
 has to be 5.
 has to be 5.
Thus, a+ 3= 5 ⇒ a = 2 
Thus, when fully simplify , the given polynomial it has degree of 4. 
That is 
 
 
 
 
Rearrange in decreasing order of degree, we have,
 which is a polynomial of degree 4.
 which is a polynomial of degree 4.