1.This can be factored using a method called DOPS (Difference of Perfect Squares), i.e. a^2 - b^2 = (a-b)(a+b).

w^2b^2-1 = (wb+1)(wb-1) = (bw+1)(bw-1)

(As a general rule of thumb, try to place your variables in alphabetical order)

3.Same thing:

s^2m^2-1 = (sm+1)(sm-1)

The other two look very ugly to factor, are you sure you typed #2 correctly?