45y^2/9y^5

To simplify the expression, you can divide the numerator and the denominator by the greatest common factor, which in this case is y^2.

So, 45y^2 divided by 9y^5 becomes:

(45/9) * (y^2/y^5) = 5 * (y^2/y^5).

Now, to divide the remaining variables with the same base (y), subtract the exponents:

5 * y^(2-5) = 5 * y^(-3).

Therefore, the simplified expression is 5y^(-3).