Statins are used to keep cholesterol in check and are a top-selling drug in the U.S. The equation: S-1.4z = 4.6 gives the amount of sales (S) of statin in billions of dollars 2 years after 1998. According to this equation, how much will/did people in the U.S. spend on statins in the year 2007? Answer: People in the U.S. will spend billion dollars on statins in 2007.