The result should be 6r2s5t2. You basically just divide the ones with the same variables. 18 and -3 has r, so divide that and get 6. The next one, 4 and 2 share the s in common, so divide them and get 2. The next has a 5 and then no number, which we assume in math means 1, shares t. So divide that and t stays 5 answer. The divide the 6 and 3 and get 2. Don't forget to bring down their variables!