1) r^8 - 1

= (r^4)^2 - (1)^2

= (r^4 - 1)(r^16 + 1r ^4 + 1)

= Not sure what to do from here

2) 4x^2 - 4x - 3 = (x+2)(2x - 1)(2x + 3)

Why do you have to make it 2x and not just have one as 4x?

3) (x^2 + 1) ^ 1/2 + 3(x^2 + 1) ^ -1/2

How do you do this???