Friday in class we learned about different types of linear relationships. When I say this I mean that we learned about decreasing and non - moving linear relationships.
For example one of the problems we did in class was problem 1.4. One part of the problem told us to make a graph of the class who took $12 out each week to buy books. The graph decreased by 12 each week and because it is a steady rate it qualifies as linear. Another problem we did was for homework. The problem was to graph 3 people who were raising money for a walkathon. One of the kids was earning $10 no matter how far she walked so her graph was a straight line from 0 meters to x meters. Since her graph steadly doesn't go anywhere it is linear. In short if the rate is steady the relationship is linear.