standard_description: Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output. (Function notation is not required in Grade 8.)
problem_activity: Warm-up
In this warm-up, students revisit quadratic expressions in different forms and what the expressions reveal about the graphs that represent them. They match equations and graphs representing two quadratic functions. The axes of the graphs are unlabeled, so students need to reason abstractly about the parameters in the expressions and the features of the graphs.
Student Facing
[IMG]
Here are graphs representing the functions
\(f\)
and
\(g\)
, given by
\(f(x) = x(x+6)\)
and
\(g(x) = x(x+6)+4\)
.
Which graph represents each function? Explain how you know.
Where does the graph of
\(f\)
meet the
\(x\)
-axis? Explain how you know.
Student Response
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Activity Synthesis
Invite students to share their matches and explanations. If one or more explanations in the Student Response are not mentioned, bring them up so that students can see multiple ways of reasoning about the equations and graphs.


aligns: no