How to find the nth term of fractions ​

Inez has a phone card. the graph shows the number of minutes that remain on her phone card a certain number of days.

Find the volume of the solid obtained by rotating the region enclosed by the curves y=1x and y=7^-x about the x-axis. (use symbolic notation and fractions where needed.) volume =

Segment wx is shown explain how you would construct a perpendicular bisector of wx using a compass and a straightedge