Simplify the equation. If all the like terms (terms that share the same variable or multiple constants) have not been simplified, you cannot know if the sum of terms is a polynomial.
Observe if there is still more than one term after simplifying. If there is, the sum of terms is a polynomial. Make sure an addition symbol is present.
Determine the polynomial by its degree. A polynomial's degree is the highest power to which a variable is raised; thus, "9x^3 + 1" is a third-degree polynomial (called a "cubic").