Answer
The given expression is a polynomial of degree $2$.
Work Step by Step
A monomial is an expression of the form $ax^{k}$,
where $x$ is the variable,
the exponent $k$, a nonnegative integer, is the degree,
and $a$ is the coefficient of the term.
A polynomial expression is either a single monomial or the SUM of several monomials.
The degree of the polynomial is the degree of the monomial with the highest degree.
This is a sum of $3x^{2}$ and $(-5)$, two monomials.
The first has degree $2$, and the second has degree $0$.
This is a polynomial of degree $2$.
