Unit 7, Lesson 15
Preparing for Vertex Form
Extra Support Materials for Algebra 1
15.1
Warm-up
Instructional Routines
Which Three Go Together?Materials
NoneActivity Narrative
This Warm-up prompts students to compare four graphs. It gives students a reason to use language precisely (MP6). It gives the teacher an opportunity to hear how students use terminology and talk about characteristics of the graphs in comparison to one another. These images were chosen to draw attention to the location of the intercepts, whether the graph of a quadratic function opens upward or downward, and the location of the vertex of the graph of a quadratic function.
Launch
Arrange students in groups of 2–4. Display the graphs for all to see. Give students 1 minute of quiet think time and ask them to indicate when they have noticed three graphs that go together and can explain why. Next, tell students to share their response with their group and then work together to find as many sets of three as they can.
Activity
NoneEach graph represents either a linear or quadratic function. Which three go together? Why do they go together?
A
B
C
D
Student Response
Activity Synthesis
Invite each group to share one reason why a particular set of three go together. Record and display the responses for all to see. After each response, ask the class if they agree or disagree. Since there is no single correct answer to the question of which three go together, attend to students’ explanations and ensure that the reasons given are correct.
During the discussion, ask students to explain the meaning of any terminology they use, such as “intercept,” “vertex,” “zero” (of a function), “opens upward,” or “opens downward” and to clarify their reasoning as needed. Consider asking:
- “How do you know ?”
- “What do you mean by ?”
- “Can you say that in another way?”