1234
of 4

Interval Notation

So,

-7 < x < 10  would be  ( -7, 10)

and

3 < x is less than or equal to 205  would be  ( 3, 205 ]

Easy!

TRY IT:

Write the interval notation for:

  2 is less than or equal to x < 5

   0 is less than or equal to x is less than or equal to 7

-6 < x < 4

-10 < x < 0

What about  x > -1  ?

Here it is on the number line:

number line showing x is greater than -1

x can't be -1, but it can be greater than -1 ... It can be 2 ... or 5,397,241.

These go on forever, so we write

( -1, infinity )

  number line showing x is greater than -1, an open dot so ( , and an arrow means this guy to infinity