Please help ASAP: A contractor records the areas, in square feet, of several houses in a neighborhood to determine data about the neighborhood. Which formula should be used to calculate the standard deviation?

Carla is saving money for a trip this summer. she already has some money in her savings account and will add the same amount to her account each week. at the end of 2? weeks, carla has? $130. at the end of 8? weeks, she has? $280. write a linear function in the form y=mx+b to represent the amount of money m that carla has saved after w weeks.