What is the slope of a line that is perpendicular to a line whose slope is 5/3?

Ineed with number 17 i don’t get it at alll

Consider the function f(x)=−2/3x+5 . what is f(1/2) ? enter your answer, as a simplified fraction, in the box. f(1/2)=

Anew shopping mall is gaining in popularity. every day since it opened, the number of shoppers is 5% more than the number of shoppers the day before. the total number of shoppers over the first 10 days is 1258 how many shoppers were on the first day?