Express in interval notation.
x < 0
The set x < 0 represents those numbers that are less than 0.
A simplified notation, called interval notation, is used for writing intervals.
The symbol < indicates that 0 is not included in the set; therefore, it would not be included in this interval.
The symbol -∞ is used to show that the interval included all real numbers less than 0. It is used in the position of the left endpoint. A parenthesis is always included next to the infinity symbol in interval notation.
Using interval notation, the set x < 0 is written as (-∞,0)