Help I do not get it

If f(x)=x^3 and g(x)=2x+7 when g(x)=-5

At a sale this week, a desk is being sold for $213. this is a 29% discount from the original price. what is the original price?

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