Answer: Yes; this is polynomial.
Specifically, it is a "polynomial EXPRESSION" ; but not a "polynomial equation" ; because it is not an "equation.
There are more than one variables/variable expressions, so it is a polynomial.
Mental way:
415 / 51.9 * 100 = 800 students in the school.
detailed way:
x is the amount of students in the school.
51.9% * x = 415
(divide both sides by 51.9% (or 0.519))
x = 800 students
To simplify this expression, you have to remember that when
a number or a variable is raised to the negative exponent you have to
reciprocate the number. In this expression, c^-8 will be reciprocated so it
will become part of the numerator. Therefore, the final answer would be
12c^8/d^2.