There are 9 people in an office with 4 different phone lines. If all the lines begin to ring at once, how many groups of 4 people can answer these lines?

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.