Given:
The polynomial is

To find:
One term which is used to add in given polynomial to make it into a 22nd degree polynomial.
Solution:
Degree of a polynomial is the highest power of the variable.
Let,

Here, the highest power of x is 19, so degree of polynomial is 19.
To make it into a 22nd degree polynomial, we need to need a term having 22 as power of x.
We can add
, where k is constant.
So add
in the given polynomial.

Now, the degree of polynomial is 22.
Therefore, the required term is
.