What is the answer to this 2^2^2^2^0?

What is x and y (use substitution? ) 5x+3y=38 and y=3x+8?

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

Peter measures the angles in a triangle. he finds that the angles are 95, 10 and 75. is he correct? explain your answer