Transcript Lesson 6-1 - Elgin Local Schools

Lesson 7-5
Graphing Systems of Inequalities
• To solve a system of inequalities, you
need to find the ordered pairs that
satisfy all the inequalities involved. One
way to do this is to graph the
inequalities on the same coordinate
plane. The solution set is represented
by the intersection, or overlap, of the
graphs.
Ex. 1
Multiply one equation to Eliminate
Solve the system of inequalities by graphing.
y < -x + 1
Y ≤ 2x + 3
x
o
y
Multiply one equation to Eliminate
Solve the system of inequalities by graphing.
y < 2x + 2
y  -x -3
x
o
y
Ex. 2
No Solution
Solve the system of inequalities by graphing.
x - y < -1
x-y>3
x
o
y
No Solution
Solve the system of inequalities by graphing.
y  -3x + 1
y  -3x -2
x
o
y
Ex. 3
Use a System of Inequalities to Solve a Problem
The middle 50% of first-year students attending Florida State
University score between 520 and 620, inclusive, on the verbal
portion of the SAT and between 530 and 630, inclusive, on the
math portion. Graph the scores that a student would need to be in
the middle 50% of the FSU freshmen.
Verbal between 520 and 620
Math between 530 and 630
800
Math Score
520  v  620
530  m  630
1000
600
400
200
200
400
600
800
Verbal Score
1000
Use a System of Inequalities to Solve a Problem
Jamail mows grass after school but his job pays only $3 per hour.
He has been offered another job as a library assistant for $6 per
hour. Because of school, his parents allow him to work at most 15
hours per week. How many hours can Jamail mow grass and work
in the library and still make at least $60 per week?
20
16
Library
G + L = 15
3G + 6L = 60
12
8
4
4
8
12
Mowing
16
20