Hey there! I'm happy to help!
This symbol is an <u>absolute value</u> symbol. It means that we are looking for that number's distance from 0. There is no such thing as a negative distance; the distances are all positive, so both ∣9∣ and ∣-9∣ have a value of 9.
Have a wonderful day and keep on learning! :D
Differnce of 2 pefect squares
a^2-b^2=(a-b)(a+b)
(p^2)^2-9^2=(p^2-9)(p^2+9)
p^2-9=(p-3)(p+3)
factored is
(p-3)(p+3)(p^2+9)
