few_shots: 
Example:
Problem/activity:
Problem 1
The table below contains single equations in a single variable, single equations in two variables, and pairs of simultaneous equations in two variables. Check the appropriate box to show whether there is no solution, exactly 1 solution, or if there is an infinite number of solutions.
|                                                          | **           No solution          ** | **           Exactly 1 solution          ** | **           Infinite number of solutions          ** |
|----------------------------------------------------------|--------------------------------------|---------------------------------------------|-------------------------------------------------------|
|                       $${9=4x+7}$$                       |                                      |                                             |                                                       |
|                       $${y=3y+5}$$                       |                                      |                                             |                                                       |
|                    $${y={x\over2}}$$                     |                                      |                                             |                                                       |
|                     $${3x+6y-9=0}$$                      |                                      |                                             |                                                       |
|    $${x=y}$$                        $${1.25x=1.25y}$$    |                                      |                                             |                                                       |
| $${9.9=6x+8y}$$                        $${9x=2.5y-8.8}$$ |                                      |                                             |                                                       |
| $${11x-2y=1.5}$$                        $${11x-2y=2.5}$$ |                                      |                                             |                                                       |
Problem 2
Kim has a small container and a large container as shown.
[IMG]
It takes 16 of the small containers to fill the large container. Three small containers leave 1.95 gallons of space in the big container.
What is the size of each of the two containers?


Concept/skill: 
Analyze and solve pairs of simultaneous linear equations.

Answer: 
Yes. The last three rows of the table in the first problem involves solving pairs of simultaneous linear equations. The second word problem can also be represented as two simultaneous linear equations.

Now, does the following problem or activity enable students to learn the full intent of the following concept or skill?

shot_info: fl_problem_001392_pos_0

8
standard_description: Graph proportional relationships, interpreting the unit rate as the slope of the graph. Compare two different proportional relationships represented in different ways. For example, compare a distance-time graph to a distance-time equation to determine which of two moving objects has greater speed.
problem_activity: Activity
In this activity, students examine equations with one variable to determine the number of solutions. In the associated Algebra lesson, students will find the number of solutions for a system of equations. In the discussion after this activity, students are asked to look for ways they can connect the number of solutions to the equation without solving.
Launch
Arrange students in groups of 2.
Demonstrate that there are three options for the number of values that make a linear equation true.
One. For example,
\(x+1 = 3\)
is only true when
\(x = 2\)
and not true for any other value of
\(x\)
.
Zero. For example,
\(x + 1 = x\)
is not true for any value of
\(x\)
.
Infinite. For example
\(x + 1 = x + 1\)
is true for any value of
\(x\)
.
Tell students that they do not need to solve any of the equations, although rewriting the equations in other forms may help students recognize the number of solutions.
Student Facing
How many values of
\(x\)
make each equation true?
\(3x + 1 = 10\)
\(2x + 12 = 2x + 10 + 2\)
\(2x = x + 2\)
\(3(x+4) = 3x + 4\)
\(\frac{2x+6}{2} = x + 6\)
\(0 = 0\)
\(x + 3x - 4 = 7(x - \frac{4}{7})\)
\(0 = 6\)
With your partner, discuss what you notice about the equations based on the number of solutions they have.
Student Response
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Activity Synthesis
The purpose of the discussion is to recognize ways to determine the number of solutions from an equation without solving. Select students to share their answers as well as what they noticed during their discussions.
To continue the discussion, consider asking:
"What do you notice about equations that have one solution?" (On each side of the equation, there are different number of
\(x\)
variables.)
"Is there a way to know whether there will be infinite or no solutions based on the original equation?" (When each side of the equation has the same number of
\(x\)
variables and the constants are also equal, there will be infinite solutions. When each side of the equation has the same number of
\(x\)
variables and the constants are not equal, there will be no solution.)


aligns: no