What is the correct answer to this question *NEED HELP QUICKLY* my grandson is currently stuck on a couple of math problems and he needs to submit this within the hour.

Perform the indicated operation. 8/a - 6/a + 7/a

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers

Suppose that 3% of all athletes are using the endurance-enhancing hormone epo (you should be able to simply compute the percentage of all athletes that are not using epo). for our purposes, a “positive” test result is one that indicates presence of epo in an athlete’s bloodstream. the probability of a positive result, given the presence of epo is .99. the probability of a negative result, when epo is not present, is .90. what is the probability that a randomly selected athlete tests positive for epo? 0.0297