#### Answer

$(3x-5)(3x+5)$

#### Work Step by Step

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