First, you can divide the 9 by 3.
That leaves us with a coefficient of 3.
Then, imagine the b^4 as bxbxbxb.
When you divide bxbxbxb by b, it is the same as taking away one of those b's from the multiplication. That leaves us with bxbxb, or b^3.
Our final answer is 3b^3.
