What does non-linear mean

The circumference of a circle is 5 pi cm. what is the area of the circle?

It says factor each expression completely 8y+48

Val and tony get paid per project. val is paid a project fee of $44 plus $12 per hour. tony is paid a project fee of $35 plus $15 per hour. write an expression to represent how much a company will pay to hire both to work the same number of hours on a project.