The sum of S of the first N. positive integers is s=1/2n (n+1). a) Plot four points (n, s) that satisfy the equation . is the equation a linear equation? explain your reasoning?
B) Does the value n=4.2 make sense in the context of the problem explain your reasoning.

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Four airplanes carrying a total of 400 passengersarrive at the detroit airport. the airplanes carry, respectively,50, 80, 110, and 160 passengers.a) one of the 400 passengers is selected uniformly at random.let x denote the number of passengers that were on theairplane carrying the randomly selected passenger. find var(x)for x as given in the problemb) one of the 4 airplane drivers is also selected uniformly atrandom. let y denote the number of passengers on the chosen driver’s airplane. find var(y) for y as given in the problem

The table shows the balance of a money market account over time. write a function that represents the balance y(in dollars) after t years.