I'm not getting the right answer for the second part.

a=(x+9)/8 , r=(x+9)/8 so I used the a/(1-r) and then multiplied by 8 and got:

(x+9) / [8-(x+9)] which goes to (x+9) / (-x-1)

Edit: Nevermind... it's summation 0 to infinity and I kept doing 1. I got it. Thanks!