Need help on 1-7 please!

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?

Jorge wants to determine the enlarged dimensions of a digital photo to be used as wallpaper on his computer screen. the original photo was 800 pixels wide by 600 pixels high. the new photo will be 1,260 pixels wide. what will the new height be?

Parabolas y=−2x^2 and y=2x^2+k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.