What is the answer to 16n2-9

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

Question 5 of 10 2 points if a population is a sample of the population could be a. registered voters; all citizens o o b. baptists; all religious people o c. people who purchased shoes; all customers o d. the entire school faculty; math teachers

Aof 12 , we to a of 4 to on a .of 4 be ?