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Here's another one:

x is less than or equal to 2

Here's the number line:

a number line showing x is less than or equal to 2, an arrow so going on forever to negative infinity, and a closed dot so ]


The interval notation is

( negative infinity, 2 ] We use a parentheses because we can't actually equal infinity.

One important thing here:

Notice that we put the  negative infinity  on the left because you always put the guys in order from left to right as they appear on the number line.


YOUR TURN:

Write the interval notation for:

x is greater than or equal to 2

x < 4

x > 0

 x is less than or equal to -3