Lesson Seed 8.EE.C.7b Linear Equation (Rally)

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Domain: Expressions and Equations
Cluster: Analyze and solve linear equations and pairs of simultaneous linear equations.
Standard: 8.EE.C.7b - Solve linear equations with rational number coefficients, including equations whose solutions require expanding expressions using the distributive property and collecting like terms.
Purpose/Big Idea:
·  Solve linear equations with rational number coefficients, including equations whose solutions require expanding expressions using the distributive property and collecting like terms.
·  Look for and make use of structure
Materials:
·  Linear Equation Rally worksheets (1 set of four per group of four students)
Activity:
1.  Explain the Equation Roundtable structure to students.
2.  Each student will be given a different problem.
3.  They will complete the first step to solve their problem and rewrite the equation.
4.  Then they will pass their paper clockwise to another person in their group.
5.  Once the students receive this second problem they will examine their group member’s work and either coach or praise their group member depending on whether they think it is right or wrong.
6.  They will then complete step two of solving this equation and rewrite the equation.
7.  This process continues until the equation makes it back to its original owner, who checks the solution for validity.
8.  Reflect on the activity by asking the Guiding Questions.
Guiding Questions:
·  How was the process the same for each of these equations? How was it different?
·  Compare and contrast solution methods for your group and the group next to you.
·  How did your group choose to check your solution, and what is the meaning of that answer?

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Set A - #1

Set A - #2

Set A - #3

Set A - #4

Possible Steps to Determine the Solutions

Set A

Set A - #1

8y - 2y +3 = 9

6y +3 = 9

6y = 6

y = 1

Set A - #2

0 = 2b + 3 + b

0 = 3b + 3

-3 = 3b

-1 = b

Set A - #3

8e+ 15 – 3e = -35

5e + 15 = -35

5e = -50

e = -10

Set A - #4

9 – 3n +15 = 30

-3n + 24 = 30

-n + 8 = 10

-2 = n

Set B - #1

34 + 12m+ 14 = 1916

Set B - #2

54p+4- 16p=23

Set B - #3

18=710y+455-y

Set B - #4

77=‾ 5.5r+6+ 14.3r

Possible Steps to Determine the Solutions

Set B

Set B - #1

34 + 12m+ 14 = 1916

34 + 12m+ 216 = 1916

1216 + 12m+ 216 = 1916

12m+ 1416 = 1916

12m = 516

m = 58

Set B - #2

54p+4- 16p=23

20p+20-16p=23

20+4p=23

4p=3

p=34

Set B - #3

18=710y+455-y

18=710y+4- 45 y

18= ‾y+4

14= ‾y

‾14=y

Set B - #4

77=‾ 5.5r+6+ 14.3r

77=‾ 5.5r+33+ 14.3r

77=8.8r+33

44=8.8r

5=r

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