Algebra Question: Need Help

Algebra Question: Need Help?
Here's the link to the question:

https://docs.google.com/file/d/0BwKex7Yln3xQMlFOdWRrZDdERzQ/edit

The answer there is d.

But when I simplify I don't arrive at that answer.

Here's my solution to that

b^2 -4b +16 (b-4) (b+4)
___________________

(b+4) (b^2+8b+16)

How do I get that b-4 answer. Please explain as well. Thanks.

24 minutes ago
- 4 days left to answer.

Additional Details


If the link is not working, here's the problem

x is equals to:

(b^2-4b+16)(b^2-16)
________________
b^3 + 64

Your mistake was in the very first step.
(b^3 + 64) = (b+4)(b^2 -4b +16) [and not (b+4)(b^2 +8b +16), u can verify by multiplying]

(b^2-4b+16)(b^2-16)
-------------------------------
(b^3+ 64)


(b^2-4b+16)(b^2-16) (b^2-4b+16)(b+4)(b-4)
=------------------------------- = -------------------------------- = (b-4)
(b^3+ 64) (b+4)(b^2 -4b +16)

So "D. (b-4)" is he correct option.