APPENDIX E

SAMPLE ACTIVITY ON LINEAR EQUATIONS USING SPREADSHEETS

 

SPREADSHEET ACTIVITY: LINEAR GRAPHS AND SLOPE

 

Objectives:

·        Using the spreadsheets, students will identify the slope of the linear equation using its equation.

·        Students will examine the effects when the values of the slope and the y-intercept change.

·        Students will offer a verbal description on the interpretation and the uses that may have the linear equations and slope in other fields.

 

1.      Consider the following linear equation:  y = 3x – 5

 

Use spreadsheets and the suggested values to complete the table below,

 

 

A

B

 

1

 

x

 

y

 

2

 

-3

 

 

3

 

-2

 

 

4

 

-1

 

 

5

 

0

 

 

6

 

1

 

 

7

 

2

 

 

8

 

3

 

 

Then, construct the graph. Please, provide a printout of your work.

 

The value of the slope and the y intercept are:

 

 

 

Describe the inclination of the straight line:

 

 

 

In two or more sentences, briefly describe the relation that you can find between the inclination of the straight line and its slope.

 

 

2.      Now, let examine what happens when the values of slope and y intercept change.  In this case, let take a bigger values to the slope and y intercept. Consider for example the following equation:

 

y = 8x + 10

 

Using spreadsheets, complete the table below:

 

 

A

B

 

1

 

x

 

y

 

2

 

-3

 

 

3

 

-2

 

 

4

 

-1

 

 

5

 

0

 

 

6

 

1

 

 

7

 

2

 

 

8

 

3

 

 

 

Draw the graph of this new equation in the same Cartesian coordinates axes.

 

The value of the slope and the y intercept are:

 

 

 

Briefly describe what you can observe between these two graphics.

 

 

 

 

 

There is a common point between both graphs? If so, determine the coordinates of this point.

 

 

 

 

 

3.      Let explore now, how if the linear graph when its slope is not a positive value.  In this case, the slope could be negative or inclusive, zero.

 

Suggest one value for the slope and other for the y intercept:

 

 

y =

 

 

x +

 

 

Using spreadsheets, construct your own table of values. The following table can help you. If you want, you can add some values.

 

 

A

B

 

1

 

x

 

y

 

2

 

 

 

 

3

 

 

 

 

4

 

 

 

 

5

 

 

 

 

6

 

 

 

 

7

 

 

 

 

8

 

 

 

 

The value of the slope and the y intercept are:

 

 

 

Using spreadsheets, construct the graph of your own linear equation, and answer the following questions:

 

What is your idea about what slope is?

 

 

 

 

Which is the biggest difference that you observed between the linear graph with positive slope and with negative slope? Explain.

 

 

 

Do you think that a slope could be bigger than other? How you can graphically show it? Use spreadsheets to justify your answer.

 

 

 

 

 

 

 

 

 

 

 

 

 

From your major or from a situation of the daily life, offer a description on tendencies that can be classified as linear. Explain your answer.

 

 

 

 

 

 

 

 

 

 

 

 

 

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