Answer:
What this is is factoring and these are both perfect squares.
(3x-5)(3x+5) is the answer.
Step-by-step explanation:
First we take the 9x^2-25 and split in in two statements
(3x-5) (3x+5)
then foil to check it
first side: 3x*3x=9x^2
outside: 3x*5=15x
inside: -5*3x=-15x
last: -5*5=-25
then put it together
9x^2+15x-15x-25
the 15x and -15x cancel each other out so you're left with 9x^2-25
