Answer:
[tex](3a-y)(3a+y)[/tex]
Step-by-step explanation:
This is a difference of squares that has the form and factors to:
[tex]a^2x^2-b^2 = (ax-b)(ax+b)[/tex]
Here take the square root of each term for the factors.
[tex]9a^2-y^2 = (3a-y)(3a+y)[/tex]
