#### Answer

$(3-5y)(3+5y)$

#### Work Step by Step

RECALL:
A difference of two square can be factored using the formula
$a^2-b^2=(a-b)(a+b)$
The given binomial can be written as:
$=3^2-(5y)^2$
The binomial above is a difference of two squares.
Factor the difference of two squares using the formula above with $a=3$ and $b=5y$ to obtain:
$=(3-5y)(3+5y)$