Is 3x^3 + 6x^2 + 5x - 9 a third degree polynomial in standard form?

Answer 1

The highest degree identifies the degree of polynomial. In this question 3x^3 is the highest degree and as it is written in descending order of exponents (which is standardize form to write polynomials). So the answer is YES

Answer 2

Short answer is yes.

The standard form is always with the degree is descending order by the exponents.