Need help asap plz help

Given the graph below state whether or not the relation is a function, and give the domain and range.

The lengths of nails produced in a factory are normally distributed with a mean of 4.91 centimeters and a standard deviation of 0.05 centimeters. find the two lengths that separate the top 4% and the bottom 4%. these lengths could serve as limits used to identify which nails should be rejected. round your answer to the nearest hundredth, if necessary.

Bring the fraction a/a-4 to a denominator of 16-a^2