Transforming to Achieve Linearity Answers

Data were recorded for a car’s fuel efficiency, in miles per gallon (mpg), and corresponding speed, in miles per hour (mph). Given the least-squares regression line, , what is the predicted fuel efficiency for a speed of 30 mph?

Given the least-squares regression line, , what is the predicted amount of an unstable element, in grams, that is left after 8 years?