Interval notation?!

[MathIsHard:(]

I just started Algebra II yesterday & I've been assigned a page about interval notation. I get the bracket and parenthesis but I don't understand how to tell if it should be less than or greater than.

 

[pka]

I just started Algebra II yesterday & I've been assigned a page about interval notation. I get the bracket and parenthesis but I don't understand how to tell if it should be less than or greater than.

I am making a guess as to what that means.
The set \(\displaystyle \{x: -1<x\le2\}\) is given by \(\displaystyle (-1,2].\)
The \(\displaystyle (\) is used because \(\displaystyle x\ne -1\) the \(\displaystyle ]\) is used because it could be \(\displaystyle x=2\).

Thus \(\displaystyle [a,b)=\{x:a\le x<b\).

If that does not help. Then post some actual problems.
But be sure to post the instructions word for word.