Answer
$3x^2-\frac{ 4 }{y^2}+\frac{ 6}{x^2y}$
Work Step by Step
We divide each term of the polynomial by the monomial as follows:
$$
\frac{9x^4y^3 - 12x^2y + 18y^2}{3x^2y^3}=\frac{9x^4y^3 }{3x^2y^3}-\frac{ 12x^2y }{3x^2y^3}+\frac{ 18y^2}{3x^2y^3}\\
=3x^2-\frac{ 4 }{y^2}+\frac{ 6}{x^2y}
.$$