Use 800+400+200+100+50+25+12.5=1587.5 to write the sigma notation that matches this setup

Sole with work in 10 years, the average number of hours of tv watched per week by teenagers dropped from 23.9 to 21.4. find the percent of change.

You got a job selling magazines door-to-door. you are paid $100 per day plus $1.50 for each magazine you sell. which recursive formula models this situation?

Write the equation in logarithmic form e^x=403.429