We can first split the second rational expression and proceed to multiplication.
`(y - 3)^2/(y^2 - 6y + 9) *(y^3 - 9y)/(y^2 - 9)`
We can rewrite the top of the frist one as: (y - 3)(y - 3).
For the bottom of the first one, we can factor it as (y - 3)(y - 3)
For the top of the second one, we can first factor out a y.
`y^3 - 9y = y(y^2 - 9)`
So, we will have:
`((y - 3)(y - 3))/((y - 3)(y - 3)) * (y(y^2 - 9))/(y^2 - 9)`
Cancel common factor on top and bottom.
So, the final answer will just be equal to y.
`((y-3)^2/(y^2-6y+9))/((y^2-9)/(y^3-9y))=` `((y-3)^2/(y-3)^2)/((y^2-9)/(y(y^2-9)))=` `1/(1/y)=y`