Answer
$9(5a+2b)(5a-2b)$
Work Step by Step
The given polynomial is
$= 225a^2-36b^2$
Factor out $9$.
$= 9(25a^2-4b^2)$
Write the the polynomial as $a^2-b^2$.
$= 9(5a)^2-(2b)^2$
Use difference of two square pattern $a^2-b^2=(a+b)(a-b)$.
We have $a=5a$ and $b=2b$.
$= 9(5a+2b)(5a-2b)$
Hence, the factor of the polynomial is $9(5a+2b)(5a-2b)$.
