Verified answer

This is a Difference of Two Squares problem

The Difference of Two squares is factored like this

(by memorization)

a²- b² = (a + b )( a - b )

So the answer to

b² - 1 is

( b + 1 )( b - 1 )

You can't(I think). It's already in it's most factorised form.

(b-1) (b+1) = b2+1b-1b-1