Simplify 1 by x+1 + 1 by x-1

For a field trip to the zoo, 4 students rode in cars and the rest filled nine busess. how many students were in each bus if 472 students were on the trip

Find the area of the region that is inside r=3cos(theta) and outside r=2-cos(theta). sketch the curves.

For the chance to be team captain, the numbers 1-30 are put in a hat and you get two chances to pick a number, without replacement. which formula correctly shows how to find the probability that you choose the number 1 and then 2?