Sarah has been running a dog-walking business since 2010. she walks dogs twice a day, takes them to the park, and returns them to their homes. each year, she has increased her fee by the same amount. the table shows what sarah charged each customer for two given years of her business:
year annual dog-walking fee
2010 $350
2014 $750

a. what is the rate of change and initial value for sarah’s business? how do you know?
b. write an equation in slope-intercept form to represent the fees that sarah charges each year.