Could you solve it? I don't know how to solve it:(

Lines a and b are perpendicular. if the slope of line a is 3, what is the slope of line b?

Renting a room at the willow tree resort costs $125 for 2 people. each additional person is $25. write an expression that shows the cost for n extra people

Emily works as a painter. for each job, it takesher 30 minutes to prepare an interior wall ofa house before she paints and 2 minutes persquare yard to paint that will. the graph belowshows the total time it would take her to do a job,based on the total area of the wallhow long does it take her to do a job when she paints a wall with an area of 15 square yards?