[-4,0) or (10,21) write this set in indicated notation in words.

Question

My teacher taught this a little too fast and I do not understand how to do it properly. Please help!:)

Answer 1

This notation is called the interval notation, where the square bracket, [, indicates the number following can be equal to the variable, and the parenthesis indicates that it cannot. 

 

Therefore, in other notation, this interval is:  -4≤x<0 or 10<x<21.  In words, x lies between -4 and 0, inclusive of -4 and exclusive of 0,  or between 10 and 21 exclusive of both.

 

I hope this clears it up.