Title: Systems of Linear Inequalities
1Systems of Linear Inequalities
2What does a system of linear inequalities look
like?
y gt 2x 1 y lt x 2
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
- There are two lines, because it is a system.
- The solution for both inequalities is the area
shaded twice.
3How can we create system of linear inequalities
- Step 1
- Graph both lines
- y lt 4 and x gt 2
- Remember how to graph lines with only one
variable. - y horizontal
- x vertical
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
4Systems of linear inequalities
Step 2 Plug in a test point y lt 4 and x gt 2 0
lt 4 0 gt -2 True True
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
(0,0)
- Step 3 Shade both areas.
- The area where they overlap is the solution for
the system.
5Example 2 Systems of Inequalities
- Step 1 Graph both lines.
- They should be in slope-intercept form (ymxb)
- y 3x lt 6 and y gt 3x 9
- 3x 3x
- y lt 3x 6
- Sometimes the lines are parallel.
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
6Example 2 Systems of Inequalities
- Step 2 Test point (0,0)
- y gt 3x 9 and y lt 3x 6
- 0 gt 3(0) 9 and 0 lt 3(0) 6
- 0 gt 0 9 and 0 lt 0 6
- 0 gt 9 and 0 lt 6
- False True
- Step 3 Shade
- No overlap, No Solution
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
                   Â
7Homeworkpg 297-298 (1-2, 5-12 all) Must
include graphs!