To see if something is a factor of something else, another way of looking at it is to take the larger number, divide it by the factor, and see if there is a remainder. If there is no remainder, it factors evenly. Lets start with 18k^7/3k^2. To divide this, we can take it one step at a time, first dividing 3 on both sides to get 6k^7/k^2. If we divide by k we get 6k^6/k. Repeat to get 6k^5. Since this number is even, it is indeed a factor.