Is {(1,9), (-3,4), (1, -7)} a function?

You can model the population of a certain city between 1955-2000 by the radical function p(x)=55,000 sqrt x-1945. using this model, in which year was the population of that city 220,000

Marcus needs to rewrite f(x) = x2 + 6x + 4 in vertex form.

George has seven boxes of five pencils. giulio three boxes of eight pencils. one of the boys arranges all his pencils equally into two groups. was this george or giulio how many are in each group explain