#### Answer

It is a polynomial $f(x) =\dfrac{-x^2}{2}+\dfrac{1}{2}$ of degree: $2$
Leading term: $\dfrac{-1}{2}x^2$
Constant: $\dfrac{1}{2}$

#### Work Step by Step

We re-arrange the given function as follows:
$g(x)=\dfrac{-x^2}{2}+\dfrac{1}{2}$
A polynomial can be defined as a function containing only terms where $x$ is raised to a positive, integer power or constant. We can see from the given function that it is a polynomial. The degree is equal to the power of the term with the highest power, so the degree is $2$. Also, the constant value is $0$.
The term with the highest degree is always known as the leading term; that is, $4x^4$.
So, it is a polynomial $f(x) =\dfrac{-x^2}{2}+\dfrac{1}{2}$ of degree: $2$
Leading term: $\dfrac{-1}{2}x^2$
Constant: $\dfrac{1}{2}$