Answer:
not a polynomial function.
f(x)=-4x+725 This is a 1 degree polynomial function.
Explanation:

Function called polynomial if it will follow below format

This is called general polynomial function.Where
all are real number.

But above given question is not following the general polynomial format,because it contains x in the denominator so this is not a polynomial function.
Example:
(1 )
,This is a polynomial function.
(2)
, This is not a polynomial function.
(3)
, This is not a polynomial function.
Maximum power of x in polynomial function is called degree of that function.But remember that the function should follow the format of polynomial function.
f(x)=-4x+725
This is a polynomial function of degree 1.