DRAWING LINEAR FUNCTIONS AS GRAPHS Slideshow 27, Mathematics Mr Richard Sasaki, Room 307

OBJECTIVES  Perform substitution to complete tables for different values of linear functions  Plot these co-ordinates as points on graphs  Compare some graphs and begin to understand how numbers in the function affect the line

BUILDING TABLES

EXAMPLE Let’s try an example Making the tables should be easy! But can you draw them neatly?

For some 8 th graders, a table may look like this…

Really, it should look like this! Even with no ruler it can look okay, try your best please!

½-4-3½-3-2½-2-1½

PLOTTING LINE GRAPHS When we draw a graph for one unknown versus another, we draw a line graph. For linear functions, the line is always straight. We take co-ordinates from each part of the table and then draw our line. Let’s draw a graph for our previous example.

(-4, -5) (-3, -3) (-2, -1) (-1, 1) (0, 3) (1, 5) (2, 7) (3, 9) (4, 11) Finally, join the dots together and extend the line. Try the last worksheets!

For my answers, assume each axis has a scale of 1:1!

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