This Warm-up refreshes the work in an earlier lesson. It prepares students to deepen their understanding of the factored form and the intercepts of a graph that represents a quadratic function.
As students work, notice how they find the y-coordinate of the y-intercept. Identify students who do so by evaluating w(0). Ask them to share during a whole-class discussion.
Arrange students in groups of 2. Give students quiet work time and then time to share their work with a partner. Follow with a whole-class discussion.
Here is a graph of a function, w, defined by w(x)=(x+1.6)(x−2). Three points on the graph are labeled.
Find the values of a,b,c,d,e, and f. Be prepared to explain your reasoning.
a=-1.6, b=0, c=2, d=0, e=0, f=-3.2
Invite students to share their responses and reasoning. If not mentioned in students’ explanations, emphasize that:
Some students may think that the numerical values in the equation correspond directly to the x-intercepts in the graph and incorrectly state that a=-2 and c=1.6. Remind them that a graph shows all pairs of x and y values that make the equation true. Consider asking these students to try substituting -2 for x and evaluating the expression to verify that w(-2)=0.
Students will have opportunities to attend to the signs or the operations in quadratic expressions in factored form, so it is not essential that this misconception is corrected at this moment.
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This Warm-up refreshes the work in an earlier lesson. It prepares students to deepen their understanding of the factored form and the intercepts of a graph that represents a quadratic function.
As students work, notice how they find the y-coordinate of the y-intercept. Identify students who do so by evaluating w(0). Ask them to share during a whole-class discussion.
Arrange students in groups of 2. Give students quiet work time and then time to share their work with a partner. Follow with a whole-class discussion.
Here is a graph of a function, w, defined by w(x)=(x+1.6)(x−2). Three points on the graph are labeled.
Find the values of a,b,c,d,e, and f. Be prepared to explain your reasoning.
a=-1.6, b=0, c=2, d=0, e=0, f=-3.2
Invite students to share their responses and reasoning. If not mentioned in students’ explanations, emphasize that:
Some students may think that the numerical values in the equation correspond directly to the x-intercepts in the graph and incorrectly state that a=-2 and c=1.6. Remind them that a graph shows all pairs of x and y values that make the equation true. Consider asking these students to try substituting -2 for x and evaluating the expression to verify that w(-2)=0.
Students will have opportunities to attend to the signs or the operations in quadratic expressions in factored form, so it is not essential that this misconception is corrected at this moment.