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

2. 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

3. BUILDING TABLES

4. EXAMPLE Let’s try an example. -4-3-201234 3 5 7 9 11 1 -3 -5 Making the tables should be easy! But can you draw them neatly?

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

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

7. -3-20123 -15-10-5051015 -4-3-201234 -5-4½-4-3½-3-2½-2-1½

8. 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.

9. -4-3-201234 -5-31357911 -4 -3 -2 -1 0 1 2 3 4 10 8 6 4 2 -2 -4 -6 -8 -10 (-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!

10. -5-4-3-2012345 -10-8-6-4-20246810 -5-4-3-2012345 -17-14-11-8-5-21471013 For my answers, assume each axis has a scale of 1:1!

11. -4-3-201234 -6-5-4-3-2012 -4-3-201234 11½22½33½44½5 -5-4-3-2012345 543210 -2-3-4-5 -4-3-2012345 -29-24-19-14-9-416111621