SYSTEMS OF LINEAR
INEQUALITIES

Solving Linear Systems of Inequalities
by Graphing
Solving Systems of Linear
Inequalities
We show the solution to a system of
linear inequalities by graphing
them.
a) This process is easier if we put the
inequalities into Slope-Intercept
Form, y = mx + b.
1.
Solving Systems of Linear
Inequalities
2.

Graph the line using the y-intercept
& slope.
a) If the inequality is < or >, make
the lines dotted.
b) If the inequality is < or >, make
the lines solid.
Solving Systems of Linear
Inequalities
3.

The solution also includes points
not on the line, so you need to
shade the region of the graph:
above the line for ‘y >’ or ‘y ≥’.
b) below the line for ‘y <’ or ‘y ≤’.
a)
Solving Systems of Linear
Inequalities
Example:
a:
b:

3x + 4y > - 4
x + 2y < 2

Put in Slope-Intercept Form:
a) 3x + 4 y > −4
4 y > − 3x − 4
3
y > − x −1
4

b) x + 2 y < 2
2 y < −x + 2
1
y < − x +1
2
Solving Systems of Linear
Inequalities
Example, continued:

3
a : y > − x −1
4

1
b : y < − x +1
2

Graph each line, make dotted or solid
and shade the correct area.
a:
dotted
shade above

b:
dotted
shade below
Solving Systems of Linear
Inequalities
a: 3x + 4y > - 4

3
a : y > − x −1
4
Solving Systems of Linear
Inequalities
a: 3x + 4y > - 4
b: x + 2y < 2

3
a : y > − x −1
4
1
b : y < − x +1
2
Solving Systems of Linear
Inequalities
a: 3x + 4y > - 4
b: x + 2y < 2

The area between the
green arrows is the
region of overlap and
thus the solution.
Solving Systems of Linear
Inequalities
a: 3x + 4y > - 4
b: x + 2y < 2

The area between the
green arrows is the
region of overlap and
thus the solution.

3.3 graph systems of linear inequalities

  • 1.
    SYSTEMS OF LINEAR INEQUALITIES SolvingLinear Systems of Inequalities by Graphing
  • 2.
    Solving Systems ofLinear Inequalities We show the solution to a system of linear inequalities by graphing them. a) This process is easier if we put the inequalities into Slope-Intercept Form, y = mx + b. 1.
  • 3.
    Solving Systems ofLinear Inequalities 2. Graph the line using the y-intercept & slope. a) If the inequality is < or >, make the lines dotted. b) If the inequality is < or >, make the lines solid.
  • 4.
    Solving Systems ofLinear Inequalities 3. The solution also includes points not on the line, so you need to shade the region of the graph: above the line for ‘y >’ or ‘y ≥’. b) below the line for ‘y <’ or ‘y ≤’. a)
  • 5.
    Solving Systems ofLinear Inequalities Example: a: b: 3x + 4y > - 4 x + 2y < 2 Put in Slope-Intercept Form: a) 3x + 4 y > −4 4 y > − 3x − 4 3 y > − x −1 4 b) x + 2 y < 2 2 y < −x + 2 1 y < − x +1 2
  • 6.
    Solving Systems ofLinear Inequalities Example, continued: 3 a : y > − x −1 4 1 b : y < − x +1 2 Graph each line, make dotted or solid and shade the correct area. a: dotted shade above b: dotted shade below
  • 7.
    Solving Systems ofLinear Inequalities a: 3x + 4y > - 4 3 a : y > − x −1 4
  • 8.
    Solving Systems ofLinear Inequalities a: 3x + 4y > - 4 b: x + 2y < 2 3 a : y > − x −1 4 1 b : y < − x +1 2
  • 9.
    Solving Systems ofLinear Inequalities a: 3x + 4y > - 4 b: x + 2y < 2 The area between the green arrows is the region of overlap and thus the solution.
  • 10.
    Solving Systems ofLinear Inequalities a: 3x + 4y > - 4 b: x + 2y < 2 The area between the green arrows is the region of overlap and thus the solution.