Why isn't a vertical line a function? What test rules it out?

Me asap! what is the slope of this line? enter your answer in the box.

There are 93 calories in a small candy bar how many calories are ther in a half dozen small candy bars?

Frank is lending $1,000 to sarah for two years. frank and sarah agree that frank should earn a real return of 4 percent per year. instructions: a. the cpi (times 100) is 100 at the time that frank makes the loan. it is expected to be 113 in one year and 127.7 in two years. what nominal rate of interest should frank charge sarah?