ANSWER TO QUESTION 1
The given expression is

To write the polynomial in descending order means we should write in decreasing powers of

So in descending order we have,

ANSWER TO QUESTION 2
When a polynomial is in simplified form and it has one term, we call it a monomial.
If a simplified polynomial has two terms,it is called a binomial.
If a simplified polynomial has three terms, it is called a trinomial.
If a simplified polynomial gas four or more terms, we just call it a polynomial.
The given polynomial

has four terms and it us in simplified form, so it is classified as polynomial.
ANSWER TO QUESTION 3.
The degree of the polynomial is the highest degree the polynomial has.
We calculate the degree by adding the exponents of the two variables of each term.
For instance the first term is


Since the highest degree is 3, we say the degree of the polynomial 3.