I am assuming that the whole polynomial is divided by 3.
(6x2 - 9x3 + 3)/3 Given
6x2/3 - 9x3/3 + 3/3 Distribute the 1/3
2x2 - 3x3 + 1 Simplify the coefficients
-3x3 + 2x2 + 1 Commutative property (change the order of terms so that the exponants are decreasing)
Writing a polynomial in standard form means that it is written with the exponants going from largest to number smallest number.