B. To plot the graph of the function, find h- and C- intercepts.
When h = 0, then C = 4.5, and we have point (0,4.5)
When C = 0, then 0 = 40h + 4.5, h = -45/400 = -0.1125, and we have point (-0.1125,0)
Plot these two points and connect them with a straight line.
Graph is attached, but you should take only that part of the graph that corresponds to points with h > 0, because the number of hours cannot be negative