I need help (more information in picture)

Which function is represented by the graph

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)