36x^9 y^5/54x^3 y^2

To simplify the expression, we can divide the coefficients and subtract the exponents of the variables:

36x^9 y^5 / 54x^3 y^2
= (36/54) * (x^9 / x^3) * (y^5 / y^2)
= (2/3) * x^(9-3) * y^(5-2)
= (2/3) * x^6 * y^3

Therefore, the simplified expression is (2/3) x^6 y^3.