Answer:The purpose of this warm-up is for students to reason about the values we can assign graphs based on which feature of the graph, such as slope and -intercept, the viewer focuses on. Since there are no numbers on the graph, it is important for students to explain how they know the sign of the slope and -intercept based on the position of the graph.
Launch
Display the three graphs for all to see. Tell students that all three graphs have the same scale. Give students 1–2 minutes of quiet work time, followed by a whole-class discussion.
Student Facing
Diego said that these graphs are ordered from smallest to largest. Mai said they are ordered from largest to smallest. But these are graphs, not numbers! What do you think Diego and Mai are thinking?
Three graphs. First line crosses the y axis above the origin, slopes down & right. Second, a horizontal line lies above the x-axis. Third line crosses the y axis below the origin, slopes up & right.
Student Response
Student responses to this activity are available at one of our IM Certified Partners
Activity Synthesis
Display the three graphs for all to see. Invite students to share what they think Diego and Mai are thinking. Encourage students to reference the graphs in their explanation. Record and display their responses for all to see. Emphasize that even though there are no numbers shown, we can tell the sign of the slope and the sign of the -intercept based on the position of the line.
Step-by-step explanation:
