Three-part inequalities on a number line
For an expression like
-1≤x<5
Split this into two i.e.
-1≤x
And
x<5
-1≤x this reads as -1 is less than or equal to x
x<5 this reads x is less than 5
These can be shown on a number line as
Or as:
i.e. without an arrow.
Example 1
Write down the inequality shown in the diagram below:
Because x is the line between the two circles this can be read as:
The ring above -5 shows that -5 is less than x
(-5<x)
The ring above +5 shows that x is less than 5
(x<5)
Joining the two together
-5<x<5
Answer:
-5<x<5
Example 2
Write down the inequality shown in the diagram below:
Because x is the line between the two inequalities this can be read as
The ring above -4 shows that -4 is less than x
(-4<x)
The circle above the 3 shows that x is less than or equal to 3
(x≤3)
Joining the two together
-4<x≤3
Answer:
-4<x≤3



