A(- 3y) = 9x^3y + 3xy^3 - 6x^2y

To simplify the expression, we can start by distributing the -3y to each term on the right side of the equation:

A(-3y) = 9x^3y + 3xy^3 - 6x^2y

This gives us:

-3Ay = 9x^3y + 3xy^3 - 6x^2y

Next, we can combine like terms on the right side of the equation. We have two terms with y, so we can add them together:

-3Ay = (9x^3 - 6x^2)y + 3xy^3

Now, we can factor out the common factor of y from the terms inside the parentheses:

-3Ay = y(9x^3 - 6x^2) + 3xy^3

Finally, we can simplify the expression further by factoring out the common factor of 3x from the terms inside the parentheses:

-3Ay = 3x(3x^2 - 2x)y + 3xy^3

So, the simplified expression is:

-3Ay = 3x(3x^2 - 2x)y + 3xy^3